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diff --git a/contrib/ncurses/misc/hackguide.doc b/contrib/ncurses/misc/hackguide.doc deleted file mode 100644 index 5fd49b3ada34..000000000000 --- a/contrib/ncurses/misc/hackguide.doc +++ /dev/null @@ -1,692 +0,0 @@ - - A Hacker's Guide to NCURSES - - Contents - - * Abstract - * Objective of the Package - + Why System V Curses? - + How to Design Extensions - * Portability and Configuration - * Documentation Conventions - * How to Report Bugs - * A Tour of the Ncurses Library - + Library Overview - + The Engine Room - + Keyboard Input - + Mouse Events - + Output and Screen Updating - * The Forms and Menu Libraries - * A Tour of the Terminfo Compiler - + Translation of Non-use Capabilities - + Use Capability Resolution - + Source-Form Translation - * Other Utilities - * Style Tips for Developers - * Porting Hints - - Abstract - - This document is a hacker's tour of the ncurses library and utilities. - It discusses design philosophy, implementation methods, and the - conventions used for coding and documentation. It is recommended - reading for anyone who is interested in porting, extending or - improving the package. - - Objective of the Package - - The objective of the ncurses package is to provide a free software API - for character-cell terminals and terminal emulators with the following - characteristics: - - * Source-compatible with historical curses implementations - (including the original BSD curses and System V curses. - * Conformant with the XSI Curses standard issued as part of XPG4 by - X/Open. - * High-quality -- stable and reliable code, wide portability, good - packaging, superior documentation. - * Featureful -- should eliminate as much of the drudgery of C - interface programming as possible, freeing programmers to think at - a higher level of design. - - These objectives are in priority order. So, for example, source - compatibility with older version must trump featurefulness -- we - cannot add features if it means breaking the portion of the API - corresponding to historical curses versions. - -Why System V Curses? - - We used System V curses as a model, reverse-engineering their API, in - order to fulfill the first two objectives. - - System V curses implementations can support BSD curses programs with - just a recompilation, so by capturing the System V API we also capture - BSD's. - - More importantly for the future, the XSI Curses standard issued by - X/Open is explicitly and closely modeled on System V. So conformance - with System V took us most of the way to base-level XSI conformance. - -How to Design Extensions - - The third objective (standards conformance) requires that it be easy - to condition source code using ncurses so that the absence of - nonstandard extensions does not break the code. - - Accordingly, we have a policy of associating with each nonstandard - extension a feature macro, so that ncurses client code can use this - macro to condition in or out the code that requires the ncurses - extension. - - For example, there is a macro NCURSES_MOUSE_VERSION which XSI Curses - does not define, but which is defined in the ncurses library header. - You can use this to condition the calls to the mouse API calls. - - Portability and Configuration - - Code written for ncurses may assume an ANSI-standard C compiler and - POSIX-compatible OS interface. It may also assume the presence of a - System-V-compatible select(2) call. - - We encourage (but do not require) developers to make the code friendly - to less-capable UNIX environments wherever possible. - - We encourage developers to support OS-specific optimizations and - methods not available under POSIX/ANSI, provided only that: - - * All such code is properly conditioned so the build process does - not attempt to compile it under a plain ANSI/POSIX environment. - * Adding such implementation methods does not introduce - incompatibilities in the ncurses API between platforms. - - We use GNU autoconf(1) as a tool to deal with portability issues. The - right way to leverage an OS-specific feature is to modify the autoconf - specification files (configure.in and aclocal.m4) to set up a new - feature macro, which you then use to condition your code. - - Documentation Conventions - - There are three kinds of documentation associated with this package. - Each has a different preferred format: - - * Package-internal files (README, INSTALL, TO-DO etc.) - * Manual pages. - * Everything else (i.e., narrative documentation). - - Our conventions are simple: - - 1. Maintain package-internal files in plain text. The expected viewer - for them more(1) or an editor window; there's no point in - elaborate mark-up. - 2. Mark up manual pages in the man macros. These have to be viewable - through traditional man(1) programs. - 3. Write everything else in HTML. - - When in doubt, HTMLize a master and use lynx(1) to generate plain - ASCII (as we do for the announcement document). - - The reason for choosing HTML is that it's (a) well-adapted for on-line - browsing through viewers that are everywhere; (b) more easily readable - as plain text than most other mark-ups, if you don't have a viewer; - and (c) carries enough information that you can generate a - nice-looking printed version from it. Also, of course, it make - exporting things like the announcement document to WWW pretty trivial. - - How to Report Bugs - - The reporting address for bugs is bug-ncurses@gnu.org. This is a - majordomo list; to join, write to bug-ncurses-request@gnu.org with a - message containing the line: - subscribe <name>@<host.domain> - - The ncurses code is maintained by a small group of volunteers. While - we try our best to fix bugs promptly, we simply don't have a lot of - hours to spend on elementary hand-holding. We rely on intelligent - cooperation from our users. If you think you have found a bug in - ncurses, there are some steps you can take before contacting us that - will help get the bug fixed quickly. - - In order to use our bug-fixing time efficiently, we put people who - show us they've taken these steps at the head of our queue. This means - that if you don't, you'll probably end up at the tail end and have to - wait a while. - - 1. Develop a recipe to reproduce the bug. - Bugs we can reproduce are likely to be fixed very quickly, often - within days. The most effective single thing you can do to get a - quick fix is develop a way we can duplicate the bad behavior -- - ideally, by giving us source for a small, portable test program - that breaks the library. (Even better is a keystroke recipe using - one of the test programs provided with the distribution.) - 2. Try to reproduce the bug on a different terminal type. - In our experience, most of the behaviors people report as library - bugs are actually due to subtle problems in terminal descriptions. - This is especially likely to be true if you're using a traditional - asynchronous terminal or PC-based terminal emulator, rather than - xterm or a UNIX console entry. - It's therefore extremely helpful if you can tell us whether or not - your problem reproduces on other terminal types. Usually you'll - have both a console type and xterm available; please tell us - whether or not your bug reproduces on both. - If you have xterm available, it is also good to collect xterm - reports for different window sizes. This is especially true if you - normally use an unusual xterm window size -- a surprising number - of the bugs we've seen are either triggered or masked by these. - 3. Generate and examine a trace file for the broken behavior. - Recompile your program with the debugging versions of the - libraries. Insert a trace() call with the argument set to - TRACE_UPDATE. (See "Writing Programs with NCURSES" for details on - trace levels.) Reproduce your bug, then look at the trace file to - see what the library was actually doing. - Another frequent cause of apparent bugs is application coding - errors that cause the wrong things to be put on the virtual - screen. Looking at the virtual-screen dumps in the trace file will - tell you immediately if this is happening, and save you from the - possible embarrassment of being told that the bug is in your code - and is your problem rather than ours. - If the virtual-screen dumps look correct but the bug persists, - it's possible to crank up the trace level to give more and more - information about the library's update actions and the control - sequences it issues to perform them. The test directory of the - distribution contains a tool for digesting these logs to make them - less tedious to wade through. - Often you'll find terminfo problems at this stage by noticing that - the escape sequences put out for various capabilities are wrong. - If not, you're likely to learn enough to be able to characterize - any bug in the screen-update logic quite exactly. - 4. Report details and symptoms, not just interpretations. - If you do the preceding two steps, it is very likely that you'll - discover the nature of the problem yourself and be able to send us - a fix. This will create happy feelings all around and earn you - good karma for the first time you run into a bug you really can't - characterize and fix yourself. - If you're still stuck, at least you'll know what to tell us. - Remember, we need details. If you guess about what is safe to - leave out, you are too likely to be wrong. - If your bug produces a bad update, include a trace file. Try to - make the trace at the least voluminous level that pins down the - bug. Logs that have been through tracemunch are OK, it doesn't - throw away any information (actually they're better than - un-munched ones because they're easier to read). - If your bug produces a core-dump, please include a symbolic stack - trace generated by gdb(1) or your local equivalent. - Tell us about every terminal on which you've reproduced the bug -- - and every terminal on which you can't. Ideally, sent us terminfo - sources for all of these (yours might differ from ours). - Include your ncurses version and your OS/machine type, of course! - You can find your ncurses version in the curses.h file. - - If your problem smells like a logic error or in cursor movement or - scrolling or a bad capability, there are a couple of tiny test frames - for the library algorithms in the progs directory that may help you - isolate it. These are not part of the normal build, but do have their - own make productions. - - The most important of these is mvcur, a test frame for the - cursor-movement optimization code. With this program, you can see - directly what control sequences will be emitted for any given cursor - movement or scroll/insert/delete operations. If you think you've got a - bad capability identified, you can disable it and test again. The - program is command-driven and has on-line help. - - If you think the vertical-scroll optimization is broken, or just want - to understand how it works better, build hashmap and read the header - comments of hardscroll.c and hashmap.c; then try it out. You can also - test the hardware-scrolling optimization separately with hardscroll. - - There's one other interactive tester, tctest, that exercises - translation between termcap and terminfo formats. If you have a - serious need to run this, you probably belong on our development team! - - A Tour of the Ncurses Library - -Library Overview - - Most of the library is superstructure -- fairly trivial convenience - interfaces to a small set of basic functions and data structures used - to manipulate the virtual screen (in particular, none of this code - does any I/O except through calls to more fundamental modules - described below). The files - - lib_addch.c lib_bkgd.c lib_box.c lib_chgat.c lib_clear.c - lib_clearok.c lib_clrbot.c lib_clreol.c lib_colorset.c lib_data.c - lib_delch.c lib_delwin.c lib_echo.c lib_erase.c lib_gen.c - lib_getstr.c lib_hline.c lib_immedok.c lib_inchstr.c lib_insch.c - lib_insdel.c lib_insstr.c lib_instr.c lib_isendwin.c lib_keyname.c - lib_leaveok.c lib_move.c lib_mvwin.c lib_overlay.c lib_pad.c - lib_printw.c lib_redrawln.c lib_scanw.c lib_screen.c lib_scroll.c - lib_scrollok.c lib_scrreg.c lib_set_term.c lib_slk.c - lib_slkatr_set.c lib_slkatrof.c lib_slkatron.c lib_slkatrset.c - lib_slkattr.c lib_slkclear.c lib_slkcolor.c lib_slkinit.c - lib_slklab.c lib_slkrefr.c lib_slkset.c lib_slktouch.c lib_touch.c - lib_unctrl.c lib_vline.c lib_wattroff.c lib_wattron.c lib_window.c - - are all in this category. They are very unlikely to need change, - barring bugs or some fundamental reorganization in the underlying data - structures. - - These files are used only for debugging support: - - lib_trace.c lib_traceatr.c lib_tracebits.c lib_tracechr.c - lib_tracedmp.c lib_tracemse.c trace_buf.c - - It is rather unlikely you will ever need to change these, unless you - want to introduce a new debug trace level for some reasoon. - - There is another group of files that do direct I/O via tputs(), - computations on the terminal capabilities, or queries to the OS - environment, but nevertheless have only fairly low complexity. These - include: - - lib_acs.c lib_beep.c lib_color.c lib_endwin.c lib_initscr.c - lib_longname.c lib_newterm.c lib_options.c lib_termcap.c lib_ti.c - lib_tparm.c lib_tputs.c lib_vidattr.c read_entry.c. - - They are likely to need revision only if ncurses is being ported to an - environment without an underlying terminfo capability representation. - - These files have serious hooks into the tty driver and signal - facilities: - - lib_kernel.c lib_baudrate.c lib_raw.c lib_tstp.c lib_twait.c - - If you run into porting snafus moving the package to another UNIX, the - problem is likely to be in one of these files. The file lib_print.c - uses sleep(2) and also falls in this category. - - Almost all of the real work is done in the files - - hardscroll.c hashmap.c lib_addch.c lib_doupdate.c lib_getch.c - lib_mouse.c lib_mvcur.c lib_refresh.c lib_setup.c lib_vidattr.c - - Most of the algorithmic complexity in the library lives in these - files. If there is a real bug in ncurses itself, it's probably here. - We'll tour some of these files in detail below (see The Engine Room). - - Finally, there is a group of files that is actually most of the - terminfo compiler. The reason this code lives in the ncurses library - is to support fallback to /etc/termcap. These files include - - alloc_entry.c captoinfo.c comp_captab.c comp_error.c comp_hash.c - comp_parse.c comp_scan.c parse_entry.c read_termcap.c write_entry.c - - We'll discuss these in the compiler tour. - -The Engine Room - - Keyboard Input - - All ncurses input funnels through the function wgetch(), defined in - lib_getch.c. This function is tricky; it has to poll for keyboard and - mouse events and do a running match of incoming input against the set - of defined special keys. - - The central data structure in this module is a FIFO queue, used to - match multiple-character input sequences against special-key - capabilities; also to implement pushback via ungetch(). - - The wgetch() code distinguishes between function key sequences and the - same sequences typed manually by doing a timed wait after each input - character that could lead a function key sequence. If the entire - sequence takes less than 1 second, it is assumed to have been - generated by a function key press. - - Hackers bruised by previous encounters with variant select(2) calls - may find the code in lib_twait.c interesting. It deals with the - problem that some BSD selects don't return a reliable time-left value. - The function timed_wait() effectively simulates a System V select. - - Mouse Events - - If the mouse interface is active, wgetch() polls for mouse events each - call, before it goes to the keyboard for input. It is up to - lib_mouse.c how the polling is accomplished; it may vary for different - devices. - - Under xterm, however, mouse event notifications come in via the - keyboard input stream. They are recognized by having the kmous - capability as a prefix. This is kind of klugey, but trying to wire in - recognition of a mouse key prefix without going through the - function-key machinery would be just too painful, and this turns out - to imply having the prefix somewhere in the function-key capabilities - at terminal-type initialization. - - This kluge only works because kmous isn't actually used by any - historic terminal type or curses implementation we know of. Best guess - is it's a relic of some forgotten experiment in-house at Bell Labs - that didn't leave any traces in the publicly-distributed System V - terminfo files. If System V or XPG4 ever gets serious about using it - again, this kluge may have to change. - - Here are some more details about mouse event handling: - - The lib_mouse()code is logically split into a lower level that accepts - event reports in a device-dependent format and an upper level that - parses mouse gestures and filters events. The mediating data structure - is a circular queue of event structures. - - Functionally, the lower level's job is to pick up primitive events and - put them on the circular queue. This can happen in one of two ways: - either (a) _nc_mouse_event() detects a series of incoming mouse - reports and queues them, or (b) code in lib_getch.c detects the kmous - prefix in the keyboard input stream and calls _nc_mouse_inline to - queue up a series of adjacent mouse reports. - - In either case, _nc_mouse_parse() should be called after the series is - accepted to parse the digested mouse reports (low-level events) into a - gesture (a high-level or composite event). - - Output and Screen Updating - - With the single exception of character echoes during a wgetnstr() call - (which simulates cooked-mode line editing in an ncurses window), the - library normally does all its output at refresh time. - - The main job is to go from the current state of the screen (as - represented in the curscr window structure) to the desired new state - (as represented in the newscr window structure), while doing as little - I/O as possible. - - The brains of this operation are the modules hashmap.c, hardscroll.c - and lib_doupdate.c; the latter two use lib_mvcur.c. Essentially, what - happens looks like this: - - The hashmap.c module tries to detect vertical motion changes between - the real and virtual screens. This information is represented by the - oldindex members in the newscr structure. These are modified by - vertical-motion and clear operations, and both are re-initialized - after each update. To this change-journalling information, the hashmap - code adds deductions made using a modified Heckel algorithm on hash - values generated from the line contents. - - The hardscroll.c module computes an optimum set of scroll, insertion, - and deletion operations to make the indices match. It calls - _nc_mvcur_scrolln() in lib_mvcur.c to do those motions. - - Then lib_doupdate.c goes to work. Its job is to do line-by-line - transformations of curscr lines to newscr lines. Its main tool is the - routine mvcur() in lib_mvcur.c. This routine does cursor-movement - optimization, attempting to get from given screen location A to given - location B in the fewest output characters posible. - - If you want to work on screen optimizations, you should use the fact - that (in the trace-enabled version of the library) enabling the - TRACE_TIMES trace level causes a report to be emitted after each - screen update giving the elapsed time and a count of characters - emitted during the update. You can use this to tell when an update - optimization improves efficiency. - - In the trace-enabled version of the library, it is also possible to - disable and re-enable various optimizations at runtime by tweaking the - variable _nc_optimize_enable. See the file include/curses.h.in for - mask values, near the end. - - The Forms and Menu Libraries - - The forms and menu libraries should work reliably in any environment - you can port ncurses to. The only portability issue anywhere in them - is what flavor of regular expressions the built-in form field type - TYPE_REGEXP will recognize. - - The configuration code prefers the POSIX regex facility, modeled on - System V's, but will settle for BSD regexps if the former isn't - available. - - Historical note: the panels code was written primarily to assist in - porting u386mon 2.0 (comp.sources.misc v14i001-4) to systems lacking - panels support; u386mon 2.10 and beyond use it. This version has been - slightly cleaned up for ncurses. - - A Tour of the Terminfo Compiler - - The ncurses implementation of tic is rather complex internally; it has - to do a trying combination of missions. This starts with the fact - that, in addition to its normal duty of compiling terminfo sources - into loadable terminfo binaries, it has to be able to handle termcap - syntax and compile that too into terminfo entries. - - The implementation therefore starts with a table-driven, dual-mode - lexical analyzer (in comp_scan.c). The lexer chooses its mode (termcap - or terminfo) based on the first `,' or `:' it finds in each entry. The - lexer does all the work of recognizing capability names and values; - the grammar above it is trivial, just "parse entries till you run out - of file". - -Translation of Non-use Capabilities - - Translation of most things besides use capabilities is pretty - straightforward. The lexical analyzer's tokenizer hands each - capability name to a hash function, which drives a table lookup. The - table entry yields an index which is used to look up the token type in - another table, and controls interpretation of the value. - - One possibly interesting aspect of the implementation is the way the - compiler tables are initialized. All the tables are generated by - various awk/sed/sh scripts from a master table include/Caps; these - scripts actually write C initializers which are linked to the - compiler. Furthermore, the hash table is generated in the same way, so - it doesn't have to be generated at compiler startup time (another - benefit of this organization is that the hash table can be in - shareable text space). - - Thus, adding a new capability is usually pretty trivial, just a matter - of adding one line to the include/Caps file. We'll have more to say - about this in the section on Source-Form Translation. - -Use Capability Resolution - - The background problem that makes tic tricky isn't the capability - translation itself, it's the resolution of use capabilities. Older - versions would not handle forward use references for this reason (that - is, a using terminal always had to follow its use target in the source - file). By doing this, they got away with a simple implementation - tactic; compile everything as it blows by, then resolve uses from - compiled entries. - - This won't do for ncurses. The problem is that that the whole - compilation process has to be embeddable in the ncurses library so - that it can be called by the startup code to translate termcap entries - on the fly. The embedded version can't go promiscuously writing - everything it translates out to disk -- for one thing, it will - typically be running with non-root permissions. - - So our tic is designed to parse an entire terminfo file into a - doubly-linked circular list of entry structures in-core, and then do - use resolution in-memory before writing everything out. This design - has other advantages: it makes forward and back use-references equally - easy (so we get the latter for free), and it makes checking for name - collisions before they're written out easy to do. - - And this is exactly how the embedded version works. But the - stand-alone user-accessible version of tic partly reverts to the - historical strategy; it writes to disk (not keeping in core) any entry - with no use references. - - This is strictly a core-economy kluge, implemented because the - terminfo master file is large enough that some core-poor systems swap - like crazy when you compile it all in memory...there have been reports - of this process taking three hours, rather than the twenty seconds or - less typical on the author's development box. - - So. The executable tic passes the entry-parser a hook that immediately - writes out the referenced entry if it has no use capabilities. The - compiler main loop refrains from adding the entry to the in-core list - when this hook fires. If some other entry later needs to reference an - entry that got written immediately, that's OK; the resolution code - will fetch it off disk when it can't find it in core. - - Name collisions will still be detected, just not as cleanly. The - write_entry() code complains before overwriting an entry that - postdates the time of tic's first call to write_entry(), Thus it will - complain about overwriting entries newly made during the tic run, but - not about overwriting ones that predate it. - -Source-Form Translation - - Another use of tic is to do source translation between various termcap - and terminfo formats. There are more variants out there than you might - think; the ones we know about are described in the captoinfo(1) manual - page. - - The translation output code (dump_entry() in ncurses/dump_entry.c) is - shared with the infocmp(1) utility. It takes the same internal - representation used to generate the binary form and dumps it to - standard output in a specified format. - - The include/Caps file has a header comment describing ways you can - specify source translations for nonstandard capabilities just by - altering the master table. It's possible to set up capability aliasing - or tell the compiler to plain ignore a given capability without - writing any C code at all. - - For circumstances where you need to do algorithmic translation, there - are functions in parse_entry.c called after the parse of each entry - that are specifically intended to encapsulate such translations. This, - for example, is where the AIX box1 capability get translated to an - acsc string. - - Other Utilities - - The infocmp utility is just a wrapper around the same entry-dumping - code used by tic for source translation. Perhaps the one interesting - aspect of the code is the use of a predicate function passed in to - dump_entry() to control which capabilities are dumped. This is - necessary in order to handle both the ordinary De-compilation case and - entry difference reporting. - - The tput and clear utilities just do an entry load followed by a - tputs() of a selected capability. - - Style Tips for Developers - - See the TO-DO file in the top-level directory of the source - distribution for additions that would be particularly useful. - - The prefix _nc_ should be used on library public functions that are - not part of the curses API in order to prevent pollution of the - application namespace. If you have to add to or modify the function - prototypes in curses.h.in, read ncurses/MKlib_gen.sh first so you can - avoid breaking XSI conformance. Please join the ncurses mailing list. - See the INSTALL file in the top level of the distribution for details - on the list. - - Look for the string FIXME in source files to tag minor bugs and - potential problems that could use fixing. - - Don't try to auto-detect OS features in the main body of the C code. - That's the job of the configuration system. - - To hold down complexity, do make your code data-driven. Especially, if - you can drive logic from a table filtered out of include/Caps, do it. - If you find you need to augment the data in that file in order to - generate the proper table, that's still preferable to ad-hoc code -- - that's why the fifth field (flags) is there. - - Have fun! - - Porting Hints - - The following notes are intended to be a first step towards DOS and - Macintosh ports of the ncurses libraries. - - The following library modules are `pure curses'; they operate only on - the curses internal structures, do all output through other curses - calls (not including tputs() and putp()) and do not call any other - UNIX routines such as signal(2) or the stdio library. Thus, they - should not need to be modified for single-terminal ports. - - lib_addch.c lib_addstr.c lib_bkgd.c lib_box.c lib_clear.c - lib_clrbot.c lib_clreol.c lib_delch.c lib_delwin.c lib_erase.c - lib_inchstr.c lib_insch.c lib_insdel.c lib_insstr.c lib_keyname.c - lib_move.c lib_mvwin.c lib_newwin.c lib_overlay.c lib_pad.c - lib_printw.c lib_refresh.c lib_scanw.c lib_scroll.c lib_scrreg.c - lib_set_term.c lib_touch.c lib_tparm.c lib_tputs.c lib_unctrl.c - lib_window.c panel.c - - This module is pure curses, but calls outstr(): - - lib_getstr.c - - These modules are pure curses, except that they use tputs() and - putp(): - - lib_beep.c lib_color.c lib_endwin.c lib_options.c lib_slk.c - lib_vidattr.c - - This modules assist in POSIX emulation on non-POSIX systems: - - sigaction.c - signal calls - - The following source files will not be needed for a - single-terminal-type port. - - alloc_entry.c captoinfo.c clear.c comp_captab.c comp_error.c - comp_hash.c comp_main.c comp_parse.c comp_scan.c dump_entry.c - infocmp.c parse_entry.c read_entry.c tput.c write_entry.c - - The following modules will use open()/read()/write()/close()/lseek() - on files, but no other OS calls. - - lib_screen.c - used to read/write screen dumps - - lib_trace.c - used to write trace data to the logfile - - Modules that would have to be modified for a port start here: - - The following modules are `pure curses' but contain assumptions - inappropriate for a memory-mapped port. - - lib_longname.c - assumes there may be multiple terminals - - lib_acs.c - assumes acs_map as a double indirection - - lib_mvcur.c - assumes cursor moves have variable cost - - lib_termcap.c - assumes there may be multiple terminals - - lib_ti.c - assumes there may be multiple terminals - - The following modules use UNIX-specific calls: - - lib_doupdate.c - input checking - - lib_getch.c - read() - - lib_initscr.c - getenv() - - lib_newterm.c - lib_baudrate.c - lib_kernel.c - various tty-manipulation and system calls - - lib_raw.c - various tty-manipulation calls - - lib_setup.c - various tty-manipulation calls - - lib_restart.c - various tty-manipulation calls - - lib_tstp.c - signal-manipulation calls - - lib_twait.c - gettimeofday(), select(). - _________________________________________________________________ - - - Eric S. Raymond <esr@snark.thyrsus.com> - - (Note: This is not the bug address!) diff --git a/contrib/ncurses/misc/hackguide.html b/contrib/ncurses/misc/hackguide.html deleted file mode 100644 index 417399a68365..000000000000 --- a/contrib/ncurses/misc/hackguide.html +++ /dev/null @@ -1,883 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 3.0//EN"> -<!-- - $Id: hackguide.html,v 1.23 1999/01/17 00:15:48 tom Exp $ ---> -<HTML> -<HEAD> -<TITLE>A Hacker's Guide to Ncurses Internals</TITLE> -<link rev="made" href="mailto:bugs-ncurses@gnu.org"> -<!-- -This document is self-contained, *except* that there is one relative link to -the ncurses-intro.html document, expected to be in the same directory with -this one. ---> -</HEAD> -<BODY> - -<H1>A Hacker's Guide to NCURSES</H1> - -<H1>Contents</H1> -<UL> -<LI><A HREF="#abstract">Abstract</A> -<P> -<LI><A HREF="#objective">Objective of the Package</A> -<UL> -<LI><A HREF="#whysvr4">Why System V Curses?</A> -<LI><A HREF="#extensions">How to Design Extensions</A> -</UL> -<LI><A HREF="#portability">Portability and Configuration</A><UL> -</UL> -<LI><A HREF="#documentation">Documentation Conventions</A> -<P> -<LI><A HREF="#bugtrack">How to Report Bugs</A> -<P> -<LI><A HREF="#ncurslib">A Tour of the Ncurses Library</A> -<UL> -<LI><A HREF="#loverview">Library Overview</A> -<LI><A HREF="#engine">The Engine Room</A> -<LI><A HREF="#input">Keyboard Input</A> -<LI><A HREF="#mouse">Mouse Events</A> -<LI><A HREF="#output">Output and Screen Updating</A> -</UL> -<LI><A HREF="#fmnote">The Forms and Menu Libraries</A> -<P> -<LI><A HREF="#tic">A Tour of the Terminfo Compiler</A> -<UL> -<LI><A HREF="#nonuse">Translation of Non-<STRONG>use</STRONG> Capabilities</A> -<LI><A HREF="#uses">Use Capability Resolution</A> -<LI><A HREF="#translation">Source-Form Translation</A> -</UL> -<LI><A HREF="#utils">Other Utilities</A> -<P> -<LI><A HREF="#style">Style Tips for Developers</A> -<P> -<LI><A HREF="#port">Porting Hints</A> -</UL> - -<H1><A NAME="abstract">Abstract</A></H1> - -This document is a hacker's tour of the <STRONG>ncurses</STRONG> library and utilities. -It discusses design philosophy, implementation methods, and the -conventions used for coding and documentation. It is recommended -reading for anyone who is interested in porting, extending or improving the -package. <P> - -<H1><A NAME="objective">Objective of the Package</A></H1> - -The objective of the <STRONG>ncurses</STRONG> package is to provide a free software API for -character-cell terminals and terminal emulators with the following -characteristics: <P> - -<UL> -<LI>Source-compatible with historical curses implementations (including - the original BSD curses and System V curses. -<P> -<LI>Conformant with the XSI Curses standard issued as part of XPG4 by - X/Open. -<P> -<LI>High-quality -- stable and reliable code, wide portability, good - packaging, superior documentation. -<P> -<LI>Featureful -- should eliminate as much of the drudgery of C interface - programming as possible, freeing programmers to think at a higher - level of design. -</UL> - -These objectives are in priority order. So, for example, source -compatibility with older version must trump featurefulness -- we cannot -add features if it means breaking the portion of the API corresponding -to historical curses versions. <P> - -<H2><A NAME="whysvr4">Why System V Curses?</A></H2> - -We used System V curses as a model, reverse-engineering their API, in -order to fulfill the first two objectives. <P> - -System V curses implementations can support BSD curses programs with -just a recompilation, so by capturing the System V API we also -capture BSD's. <P> - -More importantly for the future, the XSI Curses standard issued by X/Open -is explicitly and closely modeled on System V. So conformance with -System V took us most of the way to base-level XSI conformance. <P> - -<H2><A NAME="extensions">How to Design Extensions</A></H2> - -The third objective (standards conformance) requires that it be easy to -condition source code using <STRONG>ncurses</STRONG> so that the absence of nonstandard -extensions does not break the code. <P> - -Accordingly, we have a policy of associating with each nonstandard extension -a feature macro, so that ncurses client code can use this macro to condition -in or out the code that requires the <STRONG>ncurses</STRONG> extension. <P> - -For example, there is a macro <CODE>NCURSES_MOUSE_VERSION</CODE> which XSI Curses -does not define, but which is defined in the <STRONG>ncurses</STRONG> library header. -You can use this to condition the calls to the mouse API calls. <P> - -<H1><A NAME="portability">Portability and Configuration</A></H1> - -Code written for <STRONG>ncurses</STRONG> may assume an ANSI-standard C compiler and -POSIX-compatible OS interface. It may also assume the presence of a -System-V-compatible <EM>select(2)</EM> call. <P> - -We encourage (but do not require) developers to make the code friendly -to less-capable UNIX environments wherever possible. <P> - -We encourage developers to support OS-specific optimizations and methods -not available under POSIX/ANSI, provided only that: <P> - -<UL> -<LI>All such code is properly conditioned so the build process does not - attempt to compile it under a plain ANSI/POSIX environment. -<P> -<LI>Adding such implementation methods does not introduce incompatibilities - in the <STRONG>ncurses</STRONG> API between platforms. -</UL> - -We use GNU <CODE>autoconf(1)</CODE> as a tool to deal with portability issues. -The right way to leverage an OS-specific feature is to modify the autoconf -specification files (configure.in and aclocal.m4) to set up a new feature -macro, which you then use to condition your code. <P> - -<H1><A NAME="documentation">Documentation Conventions</A></H1> - -There are three kinds of documentation associated with this package. Each -has a different preferred format: <P> - -<UL> -<LI>Package-internal files (README, INSTALL, TO-DO etc.) -<LI>Manual pages. -<LI>Everything else (i.e., narrative documentation). -</UL> - -Our conventions are simple: <P> -<OL> -<LI><STRONG>Maintain package-internal files in plain text.</STRONG> - The expected viewer for them <EM>more(1)</EM> or an editor window; there's - no point in elaborate mark-up. <P> - -<LI><STRONG>Mark up manual pages in the man macros.</STRONG> These have to be viewable - through traditional <EM>man(1)</EM> programs. <P> - -<LI><STRONG>Write everything else in HTML.</STRONG> -</OL> - -When in doubt, HTMLize a master and use <EM>lynx(1)</EM> to generate -plain ASCII (as we do for the announcement document). <P> - -The reason for choosing HTML is that it's (a) well-adapted for on-line -browsing through viewers that are everywhere; (b) more easily readable -as plain text than most other mark-ups, if you don't have a viewer; and (c) -carries enough information that you can generate a nice-looking printed -version from it. Also, of course, it make exporting things like the -announcement document to WWW pretty trivial.<P> - -<H1><A NAME="bugtrack">How to Report Bugs</A></H1> - -The <A NAME="bugreport">reporting address for bugs</A> is -<A HREF="mailto:bug-ncurses@gnu.org">bug-ncurses@gnu.org</A>. -This is a majordomo list; to join, write -to <CODE>bug-ncurses-request@gnu.org</CODE> with a message containing the line: -<PRE> - subscribe <name>@<host.domain> -</PRE> - -The <CODE>ncurses</CODE> code is maintained by a small group of -volunteers. While we try our best to fix bugs promptly, we simply -don't have a lot of hours to spend on elementary hand-holding. We rely -on intelligent cooperation from our users. If you think you have -found a bug in <CODE>ncurses</CODE>, there are some steps you can take -before contacting us that will help get the bug fixed quickly. <P> - -In order to use our bug-fixing time efficiently, we put people who -show us they've taken these steps at the head of our queue. This -means that if you don't, you'll probably end up at the tail end and -have to wait a while. <P> - -<OL> -<LI>Develop a recipe to reproduce the bug. <P> - -Bugs we can reproduce are likely to be fixed very quickly, often -within days. The most effective single thing you can do to get a -quick fix is develop a way we can duplicate the bad behavior -- -ideally, by giving us source for a small, portable test program that -breaks the library. (Even better is a keystroke recipe using one of -the test programs provided with the distribution.) <P> - -<LI>Try to reproduce the bug on a different terminal type. <P> - -In our experience, most of the behaviors people report as library bugs -are actually due to subtle problems in terminal descriptions. This is -especially likely to be true if you're using a traditional -asynchronous terminal or PC-based terminal emulator, rather than xterm -or a UNIX console entry. <P> - -It's therefore extremely helpful if you can tell us whether or not your -problem reproduces on other terminal types. Usually you'll have both -a console type and xterm available; please tell us whether or not your -bug reproduces on both. <P> - -If you have xterm available, it is also good to collect xterm reports for -different window sizes. This is especially true if you normally use an -unusual xterm window size -- a surprising number of the bugs we've seen -are either triggered or masked by these. <P> - -<LI>Generate and examine a trace file for the broken behavior. <P> - -Recompile your program with the debugging versions of the libraries. -Insert a <CODE>trace()</CODE> call with the argument set to <CODE>TRACE_UPDATE</CODE>. -(See <A HREF="ncurses-intro.html#debugging">"Writing Programs with -NCURSES"</A> for details on trace levels.) -Reproduce your bug, then look at the trace file to see what the library -was actually doing. <P> - -Another frequent cause of apparent bugs is application coding errors -that cause the wrong things to be put on the virtual screen. Looking -at the virtual-screen dumps in the trace file will tell you immediately if -this is happening, and save you from the possible embarrassment of being -told that the bug is in your code and is your problem rather than ours. <P> - -If the virtual-screen dumps look correct but the bug persists, it's -possible to crank up the trace level to give more and more information -about the library's update actions and the control sequences it issues -to perform them. The test directory of the distribution contains a -tool for digesting these logs to make them less tedious to wade -through. <P> - -Often you'll find terminfo problems at this stage by noticing that the -escape sequences put out for various capabilities are wrong. If not, -you're likely to learn enough to be able to characterize any bug in -the screen-update logic quite exactly. <P> - -<LI>Report details and symptoms, not just interpretations. <P> - -If you do the preceding two steps, it is very likely that you'll discover -the nature of the problem yourself and be able to send us a fix. This -will create happy feelings all around and earn you good karma for the first -time you run into a bug you really can't characterize and fix yourself. <P> - -If you're still stuck, at least you'll know what to tell us. Remember, we -need details. If you guess about what is safe to leave out, you are too -likely to be wrong. <P> - -If your bug produces a bad update, include a trace file. Try to make -the trace at the <EM>least</EM> voluminous level that pins down the -bug. Logs that have been through tracemunch are OK, it doesn't throw -away any information (actually they're better than un-munched ones because -they're easier to read). <P> - -If your bug produces a core-dump, please include a symbolic stack trace -generated by gdb(1) or your local equivalent. <P> - -Tell us about every terminal on which you've reproduced the bug -- and -every terminal on which you can't. Ideally, sent us terminfo sources -for all of these (yours might differ from ours). <P> - -Include your ncurses version and your OS/machine type, of course! You can -find your ncurses version in the <CODE>curses.h</CODE> file. -</OL> - -If your problem smells like a logic error or in cursor movement or -scrolling or a bad capability, there are a couple of tiny test frames -for the library algorithms in the progs directory that may help you -isolate it. These are not part of the normal build, but do have their -own make productions. <P> - -The most important of these is <CODE>mvcur</CODE>, a test frame for the -cursor-movement optimization code. With this program, you can see -directly what control sequences will be emitted for any given cursor -movement or scroll/insert/delete operations. If you think you've got -a bad capability identified, you can disable it and test again. The -program is command-driven and has on-line help. <P> - -If you think the vertical-scroll optimization is broken, or just want to -understand how it works better, build <CODE>hashmap</CODE> and read the -header comments of <CODE>hardscroll.c</CODE> and <CODE>hashmap.c</CODE>; then try -it out. You can also test the hardware-scrolling optimization separately -with <CODE>hardscroll</CODE>. <P> - -There's one other interactive tester, <CODE>tctest</CODE>, that exercises -translation between termcap and terminfo formats. If you have a serious -need to run this, you probably belong on our development team! <P> - -<H1><A NAME="ncurslib">A Tour of the Ncurses Library</A></H1> - -<H2><A NAME="loverview">Library Overview</A></H2> - -Most of the library is superstructure -- fairly trivial convenience -interfaces to a small set of basic functions and data structures used -to manipulate the virtual screen (in particular, none of this code -does any I/O except through calls to more fundamental modules -described below). The files -<blockquote> -<CODE> -lib_addch.c -lib_bkgd.c -lib_box.c -lib_chgat.c -lib_clear.c -lib_clearok.c -lib_clrbot.c -lib_clreol.c -lib_colorset.c -lib_data.c -lib_delch.c -lib_delwin.c -lib_echo.c -lib_erase.c -lib_gen.c -lib_getstr.c -lib_hline.c -lib_immedok.c -lib_inchstr.c -lib_insch.c -lib_insdel.c -lib_insstr.c -lib_instr.c -lib_isendwin.c -lib_keyname.c -lib_leaveok.c -lib_move.c -lib_mvwin.c -lib_overlay.c -lib_pad.c -lib_printw.c -lib_redrawln.c -lib_scanw.c -lib_screen.c -lib_scroll.c -lib_scrollok.c -lib_scrreg.c -lib_set_term.c -lib_slk.c -lib_slkatr_set.c -lib_slkatrof.c -lib_slkatron.c -lib_slkatrset.c -lib_slkattr.c -lib_slkclear.c -lib_slkcolor.c -lib_slkinit.c -lib_slklab.c -lib_slkrefr.c -lib_slkset.c -lib_slktouch.c -lib_touch.c -lib_unctrl.c -lib_vline.c -lib_wattroff.c -lib_wattron.c -lib_window.c -</CODE> -</blockquote> -are all in this category. They are very -unlikely to need change, barring bugs or some fundamental -reorganization in the underlying data structures. <P> - -These files are used only for debugging support: -<blockquote><code> -lib_trace.c -lib_traceatr.c -lib_tracebits.c -lib_tracechr.c -lib_tracedmp.c -lib_tracemse.c -trace_buf.c -</blockquote></code> -It is rather unlikely you will ever need to change these, unless -you want to introduce a new debug trace level for some reasoon.<P> - -There is another group of files that do direct I/O via <EM>tputs()</EM>, -computations on the terminal capabilities, or queries to the OS -environment, but nevertheless have only fairly low complexity. These -include: -<blockquote><code> -lib_acs.c -lib_beep.c -lib_color.c -lib_endwin.c -lib_initscr.c -lib_longname.c -lib_newterm.c -lib_options.c -lib_termcap.c -lib_ti.c -lib_tparm.c -lib_tputs.c -lib_vidattr.c -read_entry.c. -</blockquote></code> -They are likely to need revision only if -ncurses is being ported to an environment without an underlying -terminfo capability representation. <P> - -These files -have serious hooks into -the tty driver and signal facilities: -<blockquote><code> -lib_kernel.c -lib_baudrate.c -lib_raw.c -lib_tstp.c -lib_twait.c -</blockquote></code> -If you run into porting snafus -moving the package to another UNIX, the problem is likely to be in one -of these files. -The file <CODE>lib_print.c</CODE> uses sleep(2) and also -falls in this category.<P> - -Almost all of the real work is done in the files -<blockquote><code> -hardscroll.c -hashmap.c -lib_addch.c -lib_doupdate.c -lib_getch.c -lib_mouse.c -lib_mvcur.c -lib_refresh.c -lib_setup.c -lib_vidattr.c -</blockquote></code> -Most of the algorithmic complexity in the -library lives in these files. -If there is a real bug in <STRONG>ncurses</STRONG> itself, it's probably here. -We'll tour some of these files in detail -below (see <A HREF="#engine">The Engine Room</A>). <P> - -Finally, there is a group of files that is actually most of the -terminfo compiler. The reason this code lives in the <STRONG>ncurses</STRONG> -library is to support fallback to /etc/termcap. These files include -<blockquote><code> -alloc_entry.c -captoinfo.c -comp_captab.c -comp_error.c -comp_hash.c -comp_parse.c -comp_scan.c -parse_entry.c -read_termcap.c -write_entry.c -</blockquote></code> -We'll discuss these in the compiler tour. <P> - -<H2><A NAME="engine">The Engine Room</A></H2> - -<H3><A NAME="input">Keyboard Input</A></H3> - -All <CODE>ncurses</CODE> input funnels through the function -<CODE>wgetch()</CODE>, defined in <CODE>lib_getch.c</CODE>. This function is -tricky; it has to poll for keyboard and mouse events and do a running -match of incoming input against the set of defined special keys. <P> - -The central data structure in this module is a FIFO queue, used to -match multiple-character input sequences against special-key -capabilities; also to implement pushback via <CODE>ungetch()</CODE>. <P> - -The <CODE>wgetch()</CODE> code distinguishes between function key -sequences and the same sequences typed manually by doing a timed wait -after each input character that could lead a function key sequence. -If the entire sequence takes less than 1 second, it is assumed to have -been generated by a function key press. <P> - -Hackers bruised by previous encounters with variant <CODE>select(2)</CODE> -calls may find the code in <CODE>lib_twait.c</CODE> interesting. It deals -with the problem that some BSD selects don't return a reliable -time-left value. The function <CODE>timed_wait()</CODE> effectively -simulates a System V select. <P> - -<H3><A NAME="mouse">Mouse Events</A></H3> - -If the mouse interface is active, <CODE>wgetch()</CODE> polls for mouse -events each call, before it goes to the keyboard for input. It is -up to <CODE>lib_mouse.c</CODE> how the polling is accomplished; it may vary -for different devices. <P> - -Under xterm, however, mouse event notifications come in via the keyboard -input stream. They are recognized by having the <STRONG>kmous</STRONG> capability -as a prefix. This is kind of klugey, but trying to wire in recognition of -a mouse key prefix without going through the function-key machinery would -be just too painful, and this turns out to imply having the prefix somewhere -in the function-key capabilities at terminal-type initialization. <P> - -This kluge only works because <STRONG>kmous</STRONG> isn't actually used by any -historic terminal type or curses implementation we know of. Best -guess is it's a relic of some forgotten experiment in-house at Bell -Labs that didn't leave any traces in the publicly-distributed System V -terminfo files. If System V or XPG4 ever gets serious about using it -again, this kluge may have to change. <P> - -Here are some more details about mouse event handling: <P> - -The <CODE>lib_mouse()</CODE>code is logically split into a lower level that -accepts event reports in a device-dependent format and an upper level that -parses mouse gestures and filters events. The mediating data structure is a -circular queue of event structures. <P> - -Functionally, the lower level's job is to pick up primitive events and -put them on the circular queue. This can happen in one of two ways: -either (a) <CODE>_nc_mouse_event()</CODE> detects a series of incoming -mouse reports and queues them, or (b) code in <CODE>lib_getch.c</CODE> detects the -<STRONG>kmous</STRONG> prefix in the keyboard input stream and calls _nc_mouse_inline -to queue up a series of adjacent mouse reports. <P> - -In either case, <CODE>_nc_mouse_parse()</CODE> should be called after the -series is accepted to parse the digested mouse reports (low-level -events) into a gesture (a high-level or composite event). <P> - -<H3><A NAME="output">Output and Screen Updating</A></H3> - -With the single exception of character echoes during a <CODE>wgetnstr()</CODE> -call (which simulates cooked-mode line editing in an ncurses window), -the library normally does all its output at refresh time. <P> - -The main job is to go from the current state of the screen (as represented -in the <CODE>curscr</CODE> window structure) to the desired new state (as -represented in the <CODE>newscr</CODE> window structure), while doing as -little I/O as possible. <P> - -The brains of this operation are the modules <CODE>hashmap.c</CODE>, -<CODE>hardscroll.c</CODE> and <CODE>lib_doupdate.c</CODE>; the latter two use -<CODE>lib_mvcur.c</CODE>. Essentially, what happens looks like this: <P> - -The <CODE>hashmap.c</CODE> module tries to detect vertical motion -changes between the real and virtual screens. This information -is represented by the oldindex members in the newscr structure. -These are modified by vertical-motion and clear operations, and both are -re-initialized after each update. To this change-journalling -information, the hashmap code adds deductions made using a modified Heckel -algorithm on hash values generated from the line contents. <P> - -The <CODE>hardscroll.c</CODE> module computes an optimum set of scroll, -insertion, and deletion operations to make the indices match. It calls -<CODE>_nc_mvcur_scrolln()</CODE> in <CODE>lib_mvcur.c</CODE> to do those motions. <P> - -Then <CODE>lib_doupdate.c</CODE> goes to work. Its job is to do line-by-line -transformations of <CODE>curscr</CODE> lines to <CODE>newscr</CODE> lines. Its main -tool is the routine <CODE>mvcur()</CODE> in <CODE>lib_mvcur.c</CODE>. This routine -does cursor-movement optimization, attempting to get from given screen -location A to given location B in the fewest output characters posible. <P> - -If you want to work on screen optimizations, you should use the fact -that (in the trace-enabled version of the library) enabling the -<CODE>TRACE_TIMES</CODE> trace level causes a report to be emitted after -each screen update giving the elapsed time and a count of characters -emitted during the update. You can use this to tell when an update -optimization improves efficiency. <P> - -In the trace-enabled version of the library, it is also possible to disable -and re-enable various optimizations at runtime by tweaking the variable -<CODE>_nc_optimize_enable</CODE>. See the file <CODE>include/curses.h.in</CODE> -for mask values, near the end. <P> - -<H1><A NAME="fmnote">The Forms and Menu Libraries</A></H1> - -The forms and menu libraries should work reliably in any environment you -can port ncurses to. The only portability issue anywhere in them is what -flavor of regular expressions the built-in form field type TYPE_REGEXP -will recognize. <P> - -The configuration code prefers the POSIX regex facility, modeled on -System V's, but will settle for BSD regexps if the former isn't available. <P> - -Historical note: the panels code was written primarily to assist in -porting u386mon 2.0 (comp.sources.misc v14i001-4) to systems lacking -panels support; u386mon 2.10 and beyond use it. This version has been -slightly cleaned up for <CODE>ncurses</CODE>. <P> - -<H1><A NAME="tic">A Tour of the Terminfo Compiler</A></H1> - -The <STRONG>ncurses</STRONG> implementation of <STRONG>tic</STRONG> is rather complex -internally; it has to do a trying combination of missions. This starts -with the fact that, in addition to its normal duty of compiling -terminfo sources into loadable terminfo binaries, it has to be able to -handle termcap syntax and compile that too into terminfo entries. <P> - -The implementation therefore starts with a table-driven, dual-mode -lexical analyzer (in <CODE>comp_scan.c</CODE>). The lexer chooses its -mode (termcap or terminfo) based on the first `,' or `:' it finds in -each entry. The lexer does all the work of recognizing capability -names and values; the grammar above it is trivial, just "parse entries -till you run out of file". <P> - -<H2><A NAME="nonuse">Translation of Non-<STRONG>use</STRONG> Capabilities</A></H2> - -Translation of most things besides <STRONG>use</STRONG> capabilities is pretty -straightforward. The lexical analyzer's tokenizer hands each capability -name to a hash function, which drives a table lookup. The table entry -yields an index which is used to look up the token type in another table, -and controls interpretation of the value. <P> - -One possibly interesting aspect of the implementation is the way the -compiler tables are initialized. All the tables are generated by various -awk/sed/sh scripts from a master table <CODE>include/Caps</CODE>; these -scripts actually write C initializers which are linked to the compiler. -Furthermore, the hash table is generated in the same way, so it doesn't -have to be generated at compiler startup time (another benefit of this -organization is that the hash table can be in shareable text space). <P> - -Thus, adding a new capability is usually pretty trivial, just a matter -of adding one line to the <CODE>include/Caps</CODE> file. We'll have more -to say about this in the section on <A HREF="#translation">Source-Form -Translation</A>. <P> - -<H2><A NAME="uses">Use Capability Resolution</A></H2> - -The background problem that makes <STRONG>tic</STRONG> tricky isn't the capability -translation itself, it's the resolution of <STRONG>use</STRONG> capabilities. Older -versions would not handle forward <STRONG>use</STRONG> references for this reason -(that is, a using terminal always had to follow its use target in the -source file). By doing this, they got away with a simple implementation -tactic; compile everything as it blows by, then resolve uses from compiled -entries. <P> - -This won't do for <STRONG>ncurses</STRONG>. The problem is that that the whole -compilation process has to be embeddable in the <STRONG>ncurses</STRONG> library -so that it can be called by the startup code to translate termcap -entries on the fly. The embedded version can't go promiscuously writing -everything it translates out to disk -- for one thing, it will typically -be running with non-root permissions. <P> - -So our <STRONG>tic</STRONG> is designed to parse an entire terminfo file into a -doubly-linked circular list of entry structures in-core, and then do -<STRONG>use</STRONG> resolution in-memory before writing everything out. This -design has other advantages: it makes forward and back use-references -equally easy (so we get the latter for free), and it makes checking for -name collisions before they're written out easy to do. <P> - -And this is exactly how the embedded version works. But the stand-alone -user-accessible version of <STRONG>tic</STRONG> partly reverts to the historical -strategy; it writes to disk (not keeping in core) any entry with no -<STRONG>use</STRONG> references. <P> - -This is strictly a core-economy kluge, implemented because the -terminfo master file is large enough that some core-poor systems swap -like crazy when you compile it all in memory...there have been reports of -this process taking <STRONG>three hours</STRONG>, rather than the twenty seconds -or less typical on the author's development box. <P> - -So. The executable <STRONG>tic</STRONG> passes the entry-parser a hook that -<EM>immediately</EM> writes out the referenced entry if it has no use -capabilities. The compiler main loop refrains from adding the entry -to the in-core list when this hook fires. If some other entry later -needs to reference an entry that got written immediately, that's OK; -the resolution code will fetch it off disk when it can't find it in -core. <P> - -Name collisions will still be detected, just not as cleanly. The -<CODE>write_entry()</CODE> code complains before overwriting an entry that -postdates the time of <STRONG>tic</STRONG>'s first call to -<CODE>write_entry()</CODE>, Thus it will complain about overwriting -entries newly made during the <STRONG>tic</STRONG> run, but not about -overwriting ones that predate it. <P> - -<H2><A NAME="translation">Source-Form Translation</A></H2> - -Another use of <STRONG>tic</STRONG> is to do source translation between various termcap -and terminfo formats. There are more variants out there than you might -think; the ones we know about are described in the <STRONG>captoinfo(1)</STRONG> -manual page. <P> - -The translation output code (<CODE>dump_entry()</CODE> in -<CODE>ncurses/dump_entry.c</CODE>) is shared with the <STRONG>infocmp(1)</STRONG> -utility. It takes the same internal representation used to generate -the binary form and dumps it to standard output in a specified -format. <P> - -The <CODE>include/Caps</CODE> file has a header comment describing ways you -can specify source translations for nonstandard capabilities just by -altering the master table. It's possible to set up capability aliasing -or tell the compiler to plain ignore a given capability without writing -any C code at all. <P> - -For circumstances where you need to do algorithmic translation, there -are functions in <CODE>parse_entry.c</CODE> called after the parse of each -entry that are specifically intended to encapsulate such -translations. This, for example, is where the AIX <STRONG>box1</STRONG> capability -get translated to an <STRONG>acsc</STRONG> string.<P> - -<H1><A NAME="utils">Other Utilities</A></H1> - -The <STRONG>infocmp</STRONG> utility is just a wrapper around the same -entry-dumping code used by <STRONG>tic</STRONG> for source translation. Perhaps -the one interesting aspect of the code is the use of a predicate -function passed in to <CODE>dump_entry()</CODE> to control which -capabilities are dumped. This is necessary in order to handle both -the ordinary De-compilation case and entry difference reporting. <P> - -The <STRONG>tput</STRONG> and <STRONG>clear</STRONG> utilities just do an entry load -followed by a <CODE>tputs()</CODE> of a selected capability. <P> - -<H1><A NAME="style">Style Tips for Developers</A></H1> - -See the TO-DO file in the top-level directory of the source distribution -for additions that would be particularly useful. <P> - -The prefix <CODE>_nc_</CODE> should be used on library public functions that are -not part of the curses API in order to prevent pollution of the -application namespace. - -If you have to add to or modify the function prototypes in curses.h.in, -read ncurses/MKlib_gen.sh first so you can avoid breaking XSI conformance. - -Please join the ncurses mailing list. See the INSTALL file in the -top level of the distribution for details on the list. <P> - -Look for the string <CODE>FIXME</CODE> in source files to tag minor bugs -and potential problems that could use fixing. <P> - -Don't try to auto-detect OS features in the main body of the C code. -That's the job of the configuration system. <P> - -To hold down complexity, do make your code data-driven. Especially, -if you can drive logic from a table filtered out of -<CODE>include/Caps</CODE>, do it. If you find you need to augment the -data in that file in order to generate the proper table, that's still -preferable to ad-hoc code -- that's why the fifth field (flags) is -there. <P> - -Have fun! <P> - -<H1><A NAME="port">Porting Hints</A></H1> - -The following notes are intended to be a first step towards DOS and Macintosh -ports of the ncurses libraries. <P> - -The following library modules are `pure curses'; they operate only on -the curses internal structures, do all output through other curses -calls (not including <CODE>tputs()</CODE> and <CODE>putp()</CODE>) and do not -call any other UNIX routines such as signal(2) or the stdio library. -Thus, they should not need to be modified for single-terminal -ports. <P> - -<blockquote><code> -lib_addch.c -lib_addstr.c -lib_bkgd.c -lib_box.c -lib_clear.c -lib_clrbot.c -lib_clreol.c -lib_delch.c -lib_delwin.c -lib_erase.c -lib_inchstr.c -lib_insch.c -lib_insdel.c -lib_insstr.c -lib_keyname.c -lib_move.c -lib_mvwin.c -lib_newwin.c -lib_overlay.c -lib_pad.c -lib_printw.c -lib_refresh.c -lib_scanw.c -lib_scroll.c -lib_scrreg.c -lib_set_term.c -lib_touch.c -lib_tparm.c -lib_tputs.c -lib_unctrl.c -lib_window.c -panel.c -</blockquote></code> -<P> - -This module is pure curses, but calls outstr(): <P> - -<blockquote><code> -lib_getstr.c -</blockquote></code> -<P> - -These modules are pure curses, except that they use <CODE>tputs()</CODE> -and <CODE>putp()</CODE>: <P> - -<blockquote><code> -lib_beep.c -lib_color.c -lib_endwin.c -lib_options.c -lib_slk.c -lib_vidattr.c -</blockquote></code> -<P> - -This modules assist in POSIX emulation on non-POSIX systems: <P> -<DL> -<DT> sigaction.c -<DD> signal calls -</DL> - -The following source files will not be needed for a -single-terminal-type port. <P> - -<blockquote><code> -alloc_entry.c -captoinfo.c -clear.c -comp_captab.c -comp_error.c -comp_hash.c -comp_main.c -comp_parse.c -comp_scan.c -dump_entry.c -infocmp.c -parse_entry.c -read_entry.c -tput.c -write_entry.c -</blockquote></code> -<P> - -The following modules will use open()/read()/write()/close()/lseek() on files, -but no other OS calls. <P> - -<DL> -<DT>lib_screen.c -<DD>used to read/write screen dumps -<DT>lib_trace.c -<DD>used to write trace data to the logfile -</DL> - -Modules that would have to be modified for a port start here: <P> - -The following modules are `pure curses' but contain assumptions inappropriate -for a memory-mapped port. <P> - -<dl> -<dt>lib_longname.c<dd>assumes there may be multiple terminals -<dt>lib_acs.c<dd>assumes acs_map as a double indirection -<dt>lib_mvcur.c<dd>assumes cursor moves have variable cost -<dt>lib_termcap.c<dd>assumes there may be multiple terminals -<dt>lib_ti.c<dd>assumes there may be multiple terminals -</dl> - -The following modules use UNIX-specific calls: - -<dl> -<dt>lib_doupdate.c<dd>input checking -<dt>lib_getch.c<dd>read() -<dt>lib_initscr.c<dd>getenv() -<dt>lib_newterm.c -<dt>lib_baudrate.c -<dt>lib_kernel.c<dd>various tty-manipulation and system calls -<dt>lib_raw.c<dd>various tty-manipulation calls -<dt>lib_setup.c<dd>various tty-manipulation calls -<dt>lib_restart.c<dd>various tty-manipulation calls -<dt>lib_tstp.c<dd>signal-manipulation calls -<dt>lib_twait.c<dd>gettimeofday(), select(). -</dl> - -<HR> -<ADDRESS>Eric S. Raymond <esr@snark.thyrsus.com></ADDRESS> -(Note: This is <EM>not</EM> the <A HREF="#bugtrack">bug address</A>!) -</BODY> -</HTML> diff --git a/contrib/ncurses/misc/ncurses-intro.doc b/contrib/ncurses/misc/ncurses-intro.doc deleted file mode 100644 index e45ca3530f20..000000000000 --- a/contrib/ncurses/misc/ncurses-intro.doc +++ /dev/null @@ -1,2530 +0,0 @@ - - Writing Programs with NCURSES - - by Eric S. Raymond and Zeyd M. Ben-Halim - updates since release 1.9.9e by Thomas Dickey - - Contents - - * Introduction - + A Brief History of Curses - + Scope of This Document - + Terminology - * The Curses Library - + An Overview of Curses - o Compiling Programs using Curses - o Updating the Screen - o Standard Windows and Function Naming Conventions - o Variables - + Using the Library - o Starting up - o Output - o Input - o Using Forms Characters - o Character Attributes and Color - o Mouse Interfacing - o Finishing Up - + Function Descriptions - o Initialization and Wrapup - o Causing Output to the Terminal - o Low-Level Capability Access - o Debugging - + Hints, Tips, and Tricks - o Some Notes of Caution - o Temporarily Leaving ncurses Mode - o Using ncurses under xterm - o Handling Multiple Terminal Screens - o Testing for Terminal Capabilities - o Tuning for Speed - o Special Features of ncurses - + Compatibility with Older Versions - o Refresh of Overlapping Windows - o Background Erase - + XSI Curses Conformance - * The Panels Library - + Compiling With the Panels Library - + Overview of Panels - + Panels, Input, and the Standard Screen - + Hiding Panels - + Miscellaneous Other Facilities - * The Menu Library - + Compiling with the menu Library - + Overview of Menus - + Selecting items - + Menu Display - + Menu Windows - + Processing Menu Input - + Miscellaneous Other Features - * The Forms Library - + Compiling with the forms Library - + Overview of Forms - + Creating and Freeing Fields and Forms - + Fetching and Changing Field Attributes - o Fetching Size and Location Data - o Changing the Field Location - o The Justification Attribute - o Field Display Attributes - o Field Option Bits - o Field Status - o Field User Pointer - + Variable-Sized Fields - + Field Validation - o TYPE_ALPHA - o TYPE_ALNUM - o TYPE_ENUM - o TYPE_INTEGER - o TYPE_NUMERIC - o TYPE_REGEXP - + Direct Field Buffer Manipulation - + Attributes of Forms - + Control of Form Display - + Input Processing in the Forms Driver - o Page Navigation Requests - o Inter-Field Navigation Requests - o Intra-Field Navigation Requests - o Scrolling Requests - o Field Editing Requests - o Order Requests - o Application Commands - + Field Change Hooks - + Field Change Commands - + Form Options - + Custom Validation Types - o Union Types - o New Field Types - o Validation Function Arguments - o Order Functions For Custom Types - o Avoiding Problems - _________________________________________________________________ - - Introduction - - This document is an introduction to programming with curses. It is not - an exhaustive reference for the curses Application Programming - Interface (API); that role is filled by the curses manual pages. - Rather, it is intended to help C programmers ease into using the - package. - - This document is aimed at C applications programmers not yet - specifically familiar with ncurses. If you are already an experienced - curses programmer, you should nevertheless read the sections on Mouse - Interfacing, Debugging, Compatibility with Older Versions, and Hints, - Tips, and Tricks. These will bring you up to speed on the special - features and quirks of the ncurses implementation. If you are not so - experienced, keep reading. - - The curses package is a subroutine library for terminal-independent - screen-painting and input-event handling which presents a high level - screen model to the programmer, hiding differences between terminal - types and doing automatic optimization of output to change one screen - full of text into another. Curses uses terminfo, which is a database - format that can describe the capabilities of thousands of different - terminals. - - The curses API may seem something of an archaism on UNIX desktops - increasingly dominated by X, Motif, and Tcl/Tk. Nevertheless, UNIX - still supports tty lines and X supports xterm(1); the curses API has - the advantage of (a) back-portability to character-cell terminals, and - (b) simplicity. For an application that does not require bit-mapped - graphics and multiple fonts, an interface implementation using curses - will typically be a great deal simpler and less expensive than one - using an X toolkit. - -A Brief History of Curses - - Historically, the first ancestor of curses was the routines written to - provide screen-handling for the game rogue; these used the - already-existing termcap database facility for describing terminal - capabilities. These routines were abstracted into a documented library - and first released with the early BSD UNIX versions. - - System III UNIX from Bell Labs featured a rewritten and much-improved - curses library. It introduced the terminfo format. Terminfo is based - on Berkeley's termcap database, but contains a number of improvements - and extensions. Parameterized capabilities strings were introduced, - making it possible to describe multiple video attributes, and colors - and to handle far more unusual terminals than possible with termcap. - In the later AT&T System V releases, curses evolved to use more - facilities and offer more capabilities, going far beyond BSD curses in - power and flexibility. - -Scope of This Document - - This document describes ncurses, a free implementation of the System V - curses API with some clearly marked extensions. It includes the - following System V curses features: - - * Support for multiple screen highlights (BSD curses could only - handle one `standout' highlight, usually reverse-video). - * Support for line- and box-drawing using forms characters. - * Recognition of function keys on input. - * Color support. - * Support for pads (windows of larger than screen size on which the - screen or a subwindow defines a viewport). - - Also, this package makes use of the insert and delete line and - character features of terminals so equipped, and determines how to - optimally use these features with no help from the programmer. It - allows arbitrary combinations of video attributes to be displayed, - even on terminals that leave ``magic cookies'' on the screen to mark - changes in attributes. - - The ncurses package can also capture and use event reports from a - mouse in some environments (notably, xterm under the X window system). - This document includes tips for using the mouse. - - The ncurses package was originated by Pavel Curtis. The original - maintainer of this package is Zeyd Ben-Halim <zmbenhal@netcom.com>. - Eric S. Raymond <esr@snark.thyrsus.com> wrote many of the new features - in versions after 1.8.1 and wrote most of this introduction. Jürgen - Pfeifer wrote all of the menu and forms code as well as the Ada95 - binding. Ongoing work is being done by Thomas Dickey and Jürgen - Pfeifer. Florian La Roche acts as the maintainer for the Free Software - Foundation, which holds the copyright on ncurses. Contact the current - maintainers at bug-ncurses@gnu.org. - - This document also describes the panels extension library, similarly - modeled on the SVr4 panels facility. This library allows you to - associate backing store with each of a stack or deck of overlapping - windows, and provides operations for moving windows around in the - stack that change their visibility in the natural way (handling window - overlaps). - - Finally, this document describes in detail the menus and forms - extension libraries, also cloned from System V, which support easy - construction and sequences of menus and fill-in forms. - -Terminology - - In this document, the following terminology is used with reasonable - consistency: - - window - A data structure describing a sub-rectangle of the screen - (possibly the entire screen). You can write to a window as - though it were a miniature screen, scrolling independently of - other windows on the physical screen. - - screens - A subset of windows which are as large as the terminal screen, - i.e., they start at the upper left hand corner and encompass - the lower right hand corner. One of these, stdscr, is - automatically provided for the programmer. - - terminal screen - The package's idea of what the terminal display currently looks - like, i.e., what the user sees now. This is a special screen. - - The Curses Library - -An Overview of Curses - - Compiling Programs using Curses - - In order to use the library, it is necessary to have certain types and - variables defined. Therefore, the programmer must have a line: - #include <curses.h> - - at the top of the program source. The screen package uses the Standard - I/O library, so <curses.h> includes <stdio.h>. <curses.h> also - includes <termios.h>, <termio.h>, or <sgtty.h> depending on your - system. It is redundant (but harmless) for the programmer to do these - includes, too. In linking with curses you need to have -lncurses in - your LDFLAGS or on the command line. There is no need for any other - libraries. - - Updating the Screen - - In order to update the screen optimally, it is necessary for the - routines to know what the screen currently looks like and what the - programmer wants it to look like next. For this purpose, a data type - (structure) named WINDOW is defined which describes a window image to - the routines, including its starting position on the screen (the (y, - x) coordinates of the upper left hand corner) and its size. One of - these (called curscr, for current screen) is a screen image of what - the terminal currently looks like. Another screen (called stdscr, for - standard screen) is provided by default to make changes on. - - A window is a purely internal representation. It is used to build and - store a potential image of a portion of the terminal. It doesn't bear - any necessary relation to what is really on the terminal screen; it's - more like a scratchpad or write buffer. - - To make the section of physical screen corresponding to a window - reflect the contents of the window structure, the routine refresh() - (or wrefresh() if the window is not stdscr) is called. - - A given physical screen section may be within the scope of any number - of overlapping windows. Also, changes can be made to windows in any - order, without regard to motion efficiency. Then, at will, the - programmer can effectively say ``make it look like this,'' and let the - package implementation determine the most efficient way to repaint the - screen. - - Standard Windows and Function Naming Conventions - - As hinted above, the routines can use several windows, but two are - automatically given: curscr, which knows what the terminal looks like, - and stdscr, which is what the programmer wants the terminal to look - like next. The user should never actually access curscr directly. - Changes should be made to through the API, and then the routine - refresh() (or wrefresh()) called. - - Many functions are defined to use stdscr as a default screen. For - example, to add a character to stdscr, one calls addch() with the - desired character as argument. To write to a different window. use the - routine waddch() (for `w'indow-specific addch()) is provided. This - convention of prepending function names with a `w' when they are to be - applied to specific windows is consistent. The only routines which do - not follow it are those for which a window must always be specified. - - In order to move the current (y, x) coordinates from one point to - another, the routines move() and wmove() are provided. However, it is - often desirable to first move and then perform some I/O operation. In - order to avoid clumsiness, most I/O routines can be preceded by the - prefix 'mv' and the desired (y, x) coordinates prepended to the - arguments to the function. For example, the calls - move(y, x); - addch(ch); - - can be replaced by - mvaddch(y, x, ch); - - and - wmove(win, y, x); - waddch(win, ch); - - can be replaced by - mvwaddch(win, y, x, ch); - - Note that the window description pointer (win) comes before the added - (y, x) coordinates. If a function requires a window pointer, it is - always the first parameter passed. - - Variables - - The curses library sets some variables describing the terminal - capabilities. - type name description - ------------------------------------------------------------------ - int LINES number of lines on the terminal - int COLS number of columns on the terminal - - The curses.h also introduces some #define constants and types of - general usefulness: - - bool - boolean type, actually a `char' (e.g., bool doneit;) - - TRUE - boolean `true' flag (1). - - FALSE - boolean `false' flag (0). - - ERR - error flag returned by routines on a failure (-1). - - OK - error flag returned by routines when things go right. - -Using the Library - - Now we describe how to actually use the screen package. In it, we - assume all updating, reading, etc. is applied to stdscr. These - instructions will work on any window, providing you change the - function names and parameters as mentioned above. - - Here is a sample program to motivate the discussion: - -#include <curses.h> -#include <signal.h> - -static void finish(int sig); - -main(int argc, char *argv[]) -{ - /* initialize your non-curses data structures here */ - - (void) signal(SIGINT, finish); /* arrange interrupts to terminate */ - - (void) initscr(); /* initialize the curses library */ - keypad(stdscr, TRUE); /* enable keyboard mapping */ - (void) nonl(); /* tell curses not to do NL->CR/NL on output */ - (void) cbreak(); /* take input chars one at a time, no wait for \n */ - (void) noecho(); /* don't echo input */ - - if (has_colors()) - { - start_color(); - - /* - * Simple color assignment, often all we need. - */ - init_pair(COLOR_BLACK, COLOR_BLACK, COLOR_BLACK); - init_pair(COLOR_GREEN, COLOR_GREEN, COLOR_BLACK); - init_pair(COLOR_RED, COLOR_RED, COLOR_BLACK); - init_pair(COLOR_CYAN, COLOR_CYAN, COLOR_BLACK); - init_pair(COLOR_WHITE, COLOR_WHITE, COLOR_BLACK); - init_pair(COLOR_MAGENTA, COLOR_MAGENTA, COLOR_BLACK); - init_pair(COLOR_BLUE, COLOR_BLUE, COLOR_BLACK); - init_pair(COLOR_YELLOW, COLOR_YELLOW, COLOR_BLACK); - } - - for (;;) - { - int c = getch(); /* refresh, accept single keystroke of input */ - - /* process the command keystroke */ - } - - finish(0); /* we're done */ -} - -static void finish(int sig) -{ - endwin(); - - /* do your non-curses wrapup here */ - - exit(0); -} - - Starting up - - In order to use the screen package, the routines must know about - terminal characteristics, and the space for curscr and stdscr must be - allocated. These function initscr() does both these things. Since it - must allocate space for the windows, it can overflow memory when - attempting to do so. On the rare occasions this happens, initscr() - will terminate the program with an error message. initscr() must - always be called before any of the routines which affect windows are - used. If it is not, the program will core dump as soon as either - curscr or stdscr are referenced. However, it is usually best to wait - to call it until after you are sure you will need it, like after - checking for startup errors. Terminal status changing routines like - nl() and cbreak() should be called after initscr(). - - Once the screen windows have been allocated, you can set them up for - your program. If you want to, say, allow a screen to scroll, use - scrollok(). If you want the cursor to be left in place after the last - change, use leaveok(). If this isn't done, refresh() will move the - cursor to the window's current (y, x) coordinates after updating it. - - You can create new windows of your own using the functions newwin(), - derwin(), and subwin(). The routine delwin() will allow you to get rid - of old windows. All the options described above can be applied to any - window. - - Output - - Now that we have set things up, we will want to actually update the - terminal. The basic functions used to change what will go on a window - are addch() and move(). addch() adds a character at the current (y, x) - coordinates. move() changes the current (y, x) coordinates to whatever - you want them to be. It returns ERR if you try to move off the window. - As mentioned above, you can combine the two into mvaddch() to do both - things at once. - - The other output functions, such as addstr() and printw(), all call - addch() to add characters to the window. - - After you have put on the window what you want there, when you want - the portion of the terminal covered by the window to be made to look - like it, you must call refresh(). In order to optimize finding - changes, refresh() assumes that any part of the window not changed - since the last refresh() of that window has not been changed on the - terminal, i.e., that you have not refreshed a portion of the terminal - with an overlapping window. If this is not the case, the routine - touchwin() is provided to make it look like the entire window has been - changed, thus making refresh() check the whole subsection of the - terminal for changes. - - If you call wrefresh() with curscr as its argument, it will make the - screen look like curscr thinks it looks like. This is useful for - implementing a command which would redraw the screen in case it get - messed up. - - Input - - The complementary function to addch() is getch() which, if echo is - set, will call addch() to echo the character. Since the screen package - needs to know what is on the terminal at all times, if characters are - to be echoed, the tty must be in raw or cbreak mode. Since initially - the terminal has echoing enabled and is in ordinary ``cooked'' mode, - one or the other has to changed before calling getch(); otherwise, the - program's output will be unpredictable. - - When you need to accept line-oriented input in a window, the functions - wgetstr() and friends are available. There is even a wscanw() function - that can do scanf()(3)-style multi-field parsing on window input. - These pseudo-line-oriented functions turn on echoing while they - execute. - - The example code above uses the call keypad(stdscr, TRUE) to enable - support for function-key mapping. With this feature, the getch() code - watches the input stream for character sequences that correspond to - arrow and function keys. These sequences are returned as - pseudo-character values. The #define values returned are listed in the - curses.h The mapping from sequences to #define values is determined by - key_ capabilities in the terminal's terminfo entry. - - Using Forms Characters - - The addch() function (and some others, including box() and border()) - can accept some pseudo-character arguments which are specially defined - by ncurses. These are #define values set up in the curses.h header; - see there for a complete list (look for the prefix ACS_). - - The most useful of the ACS defines are the forms-drawing characters. - You can use these to draw boxes and simple graphs on the screen. If - the terminal does not have such characters, curses.h will map them to - a recognizable (though ugly) set of ASCII defaults. - - Character Attributes and Color - - The ncurses package supports screen highlights including standout, - reverse-video, underline, and blink. It also supports color, which is - treated as another kind of highlight. - - Highlights are encoded, internally, as high bits of the - pseudo-character type (chtype) that curses.h uses to represent the - contents of a screen cell. See the curses.h header file for a complete - list of highlight mask values (look for the prefix A_). - - There are two ways to make highlights. One is to logical-or the value - of the highlights you want into the character argument of an addch() - call, or any other output call that takes a chtype argument. - - The other is to set the current-highlight value. This is logical-or'ed - with any highlight you specify the first way. You do this with the - functions attron(), attroff(), and attrset(); see the manual pages for - details. Color is a special kind of highlight. The package actually - thinks in terms of color pairs, combinations of foreground and - background colors. The sample code above sets up eight color pairs, - all of the guaranteed-available colors on black. Note that each color - pair is, in effect, given the name of its foreground color. Any other - range of eight non-conflicting values could have been used as the - first arguments of the init_pair() values. - - Once you've done an init_pair() that creates color-pair N, you can use - COLOR_PAIR(N) as a highlight that invokes that particular color - combination. Note that COLOR_PAIR(N), for constant N, is itself a - compile-time constant and can be used in initializers. - - Mouse Interfacing - - The ncurses library also provides a mouse interface. - - NOTE: this facility is specific to ncurses, it is not part of - either the XSI Curses standard, nor of System V Release 4, nor BSD - curses. System V Release 4 curses contains code with similar - interface definitions, however it is not documented. Other than by - disassembling the library, we have no way to determine exactly how - that mouse code works. Thus, we recommend that you wrap - mouse-related code in an #ifdef using the feature macro - NCURSES_MOUSE_VERSION so it will not be compiled and linked on - non-ncurses systems. - - Presently, mouse event reporting works in the following environments: - * xterm and similar programs such as rxvt. - * Linux console, when configured with gpm(1), Alessandro Rubini's - mouse server. - * OS/2 EMX - - The mouse interface is very simple. To activate it, you use the - function mousemask(), passing it as first argument a bit-mask that - specifies what kinds of events you want your program to be able to - see. It will return the bit-mask of events that actually become - visible, which may differ from the argument if the mouse device is not - capable of reporting some of the event types you specify. - - Once the mouse is active, your application's command loop should watch - for a return value of KEY_MOUSE from wgetch(). When you see this, a - mouse event report has been queued. To pick it off the queue, use the - function getmouse() (you must do this before the next wgetch(), - otherwise another mouse event might come in and make the first one - inaccessible). - - Each call to getmouse() fills a structure (the address of which you'll - pass it) with mouse event data. The event data includes zero-origin, - screen-relative character-cell coordinates of the mouse pointer. It - also includes an event mask. Bits in this mask will be set, - corresponding to the event type being reported. - - The mouse structure contains two additional fields which may be - significant in the future as ncurses interfaces to new kinds of - pointing device. In addition to x and y coordinates, there is a slot - for a z coordinate; this might be useful with touch-screens that can - return a pressure or duration parameter. There is also a device ID - field, which could be used to distinguish between multiple pointing - devices. - - The class of visible events may be changed at any time via - mousemask(). Events that can be reported include presses, releases, - single-, double- and triple-clicks (you can set the maximum - button-down time for clicks). If you don't make clicks visible, they - will be reported as press-release pairs. In some environments, the - event mask may include bits reporting the state of shift, alt, and - ctrl keys on the keyboard during the event. - - A function to check whether a mouse event fell within a given window - is also supplied. You can use this to see whether a given window - should consider a mouse event relevant to it. - - Because mouse event reporting will not be available in all - environments, it would be unwise to build ncurses applications that - require the use of a mouse. Rather, you should use the mouse as a - shortcut for point-and-shoot commands your application would normally - accept from the keyboard. Two of the test games in the ncurses - distribution (bs and knight) contain code that illustrates how this - can be done. - - See the manual page curs_mouse(3X) for full details of the - mouse-interface functions. - - Finishing Up - - In order to clean up after the ncurses routines, the routine endwin() - is provided. It restores tty modes to what they were when initscr() - was first called, and moves the cursor down to the lower-left corner. - Thus, anytime after the call to initscr, endwin() should be called - before exiting. - -Function Descriptions - - We describe the detailed behavior of some important curses functions - here, as a supplement to the manual page descriptions. - - Initialization and Wrapup - - initscr() - The first function called should almost always be initscr(). - This will determine the terminal type and initialize curses - data structures. initscr() also arranges that the first call to - refresh() will clear the screen. If an error occurs a message - is written to standard error and the program exits. Otherwise - it returns a pointer to stdscr. A few functions may be called - before initscr (slk_init(), filter(), ripofflines(), use_env(), - and, if you are using multiple terminals, newterm().) - - endwin() - Your program should always call endwin() before exiting or - shelling out of the program. This function will restore tty - modes, move the cursor to the lower left corner of the screen, - reset the terminal into the proper non-visual mode. Calling - refresh() or doupdate() after a temporary escape from the - program will restore the ncurses screen from before the escape. - - newterm(type, ofp, ifp) - A program which outputs to more than one terminal should use - newterm() instead of initscr(). newterm() should be called once - for each terminal. It returns a variable of type SCREEN * which - should be saved as a reference to that terminal. The arguments - are the type of the terminal (a string) and FILE pointers for - the output and input of the terminal. If type is NULL then the - environment variable $TERM is used. endwin() should called once - at wrapup time for each terminal opened using this function. - - set_term(new) - This function is used to switch to a different terminal - previously opened by newterm(). The screen reference for the - new terminal is passed as the parameter. The previous terminal - is returned by the function. All other calls affect only the - current terminal. - - delscreen(sp) - The inverse of newterm(); deallocates the data structures - associated with a given SCREEN reference. - - Causing Output to the Terminal - - refresh() and wrefresh(win) - These functions must be called to actually get any output on - the terminal, as other routines merely manipulate data - structures. wrefresh() copies the named window to the physical - terminal screen, taking into account what is already there in - order to do optimizations. refresh() does a refresh of - stdscr(). Unless leaveok() has been enabled, the physical - cursor of the terminal is left at the location of the window's - cursor. - - doupdate() and wnoutrefresh(win) - These two functions allow multiple updates with more efficiency - than wrefresh. To use them, it is important to understand how - curses works. In addition to all the window structures, curses - keeps two data structures representing the terminal screen: a - physical screen, describing what is actually on the screen, and - a virtual screen, describing what the programmer wants to have - on the screen. wrefresh works by first copying the named window - to the virtual screen (wnoutrefresh()), and then calling the - routine to update the screen (doupdate()). If the programmer - wishes to output several windows at once, a series of calls to - wrefresh will result in alternating calls to wnoutrefresh() and - doupdate(), causing several bursts of output to the screen. By - calling wnoutrefresh() for each window, it is then possible to - call doupdate() once, resulting in only one burst of output, - with fewer total characters transmitted (this also avoids a - visually annoying flicker at each update). - - Low-Level Capability Access - - setupterm(term, filenum, errret) - This routine is called to initialize a terminal's description, - without setting up the curses screen structures or changing the - tty-driver mode bits. term is the character string representing - the name of the terminal being used. filenum is the UNIX file - descriptor of the terminal to be used for output. errret is a - pointer to an integer, in which a success or failure indication - is returned. The values returned can be 1 (all is well), 0 (no - such terminal), or -1 (some problem locating the terminfo - database). - - The value of term can be given as NULL, which will cause the - value of TERM in the environment to be used. The errret pointer - can also be given as NULL, meaning no error code is wanted. If - errret is defaulted, and something goes wrong, setupterm() will - print an appropriate error message and exit, rather than - returning. Thus, a simple program can call setupterm(0, 1, 0) - and not worry about initialization errors. - - After the call to setupterm(), the global variable cur_term is - set to point to the current structure of terminal capabilities. - By calling setupterm() for each terminal, and saving and - restoring cur_term, it is possible for a program to use two or - more terminals at once. Setupterm() also stores the names - section of the terminal description in the global character - array ttytype[]. Subsequent calls to setupterm() will overwrite - this array, so you'll have to save it yourself if need be. - - Debugging - - NOTE: These functions are not part of the standard curses API! - - trace() - This function can be used to explicitly set a trace level. If - the trace level is nonzero, execution of your program will - generate a file called `trace' in the current working directory - containing a report on the library's actions. Higher trace - levels enable more detailed (and verbose) reporting -- see - comments attached to TRACE_ defines in the curses.h file for - details. (It is also possible to set a trace level by assigning - a trace level value to the environment variable NCURSES_TRACE). - - _tracef() - This function can be used to output your own debugging - information. It is only available only if you link with - -lncurses_g. It can be used the same way as printf(), only it - outputs a newline after the end of arguments. The output goes - to a file called trace in the current directory. - - Trace logs can be difficult to interpret due to the sheer volume of - data dumped in them. There is a script called tracemunch included with - the ncurses distribution that can alleviate this problem somewhat; it - compacts long sequences of similar operations into more succinct - single-line pseudo-operations. These pseudo-ops can be distinguished - by the fact that they are named in capital letters. - -Hints, Tips, and Tricks - - The ncurses manual pages are a complete reference for this library. In - the remainder of this document, we discuss various useful methods that - may not be obvious from the manual page descriptions. - - Some Notes of Caution - - If you find yourself thinking you need to use noraw() or nocbreak(), - think again and move carefully. It's probably better design to use - getstr() or one of its relatives to simulate cooked mode. The noraw() - and nocbreak() functions try to restore cooked mode, but they may end - up clobbering some control bits set before you started your - application. Also, they have always been poorly documented, and are - likely to hurt your application's usability with other curses - libraries. - - Bear in mind that refresh() is a synonym for wrefresh(stdscr). Don't - try to mix use of stdscr with use of windows declared by newwin(); a - refresh() call will blow them off the screen. The right way to handle - this is to use subwin(), or not touch stdscr at all and tile your - screen with declared windows which you then wnoutrefresh() somewhere - in your program event loop, with a single doupdate() call to trigger - actual repainting. - - You are much less likely to run into problems if you design your - screen layouts to use tiled rather than overlapping windows. - Historically, curses support for overlapping windows has been weak, - fragile, and poorly documented. The ncurses library is not yet an - exception to this rule. - - There is a panels library included in the ncurses distribution that - does a pretty good job of strengthening the overlapping-windows - facilities. - - Try to avoid using the global variables LINES and COLS. Use getmaxyx() - on the stdscr context instead. Reason: your code may be ported to run - in an environment with window resizes, in which case several screens - could be open with different sizes. - - Temporarily Leaving NCURSES Mode - - Sometimes you will want to write a program that spends most of its - time in screen mode, but occasionally returns to ordinary `cooked' - mode. A common reason for this is to support shell-out. This behavior - is simple to arrange in ncurses. - - To leave ncurses mode, call endwin() as you would if you were - intending to terminate the program. This will take the screen back to - cooked mode; you can do your shell-out. When you want to return to - ncurses mode, simply call refresh() or doupdate(). This will repaint - the screen. - - There is a boolean function, isendwin(), which code can use to test - whether ncurses screen mode is active. It returns TRUE in the interval - between an endwin() call and the following refresh(), FALSE otherwise. - - Here is some sample code for shellout: - addstr("Shelling out..."); - def_prog_mode(); /* save current tty modes */ - endwin(); /* restore original tty modes */ - system("sh"); /* run shell */ - addstr("returned.\n"); /* prepare return message */ - refresh(); /* restore save modes, repaint screen */ - - Using NCURSES under XTERM - - A resize operation in X sends SIGWINCH to the application running - under xterm. The ncurses library provides an experimental signal - handler, but in general does not catch this signal, because it cannot - know how you want the screen re-painted. You will usually have to - write the SIGWINCH handler yourself. Ncurses can give you some help. - - The easiest way to code your SIGWINCH handler is to have it do an - endwin, followed by an refresh and a screen repaint you code yourself. - The refresh will pick up the new screen size from the xterm's - environment. - - That is the standard way, of course (it even works with some vendor's - curses implementations). Its drawback is that it clears the screen to - reinitialize the display, and does not resize subwindows which must be - shrunk. Ncurses provides an extension which works better, the - resizeterm function. That function ensures that all windows are - limited to the new screen dimensions, and pads stdscr with blanks if - the screen is larger. - - Finally, ncurses can be configured to provide its own SIGWINCH - handler, based on resizeterm. - - Handling Multiple Terminal Screens - - The initscr() function actually calls a function named newterm() to do - most of its work. If you are writing a program that opens multiple - terminals, use newterm() directly. - - For each call, you will have to specify a terminal type and a pair of - file pointers; each call will return a screen reference, and stdscr - will be set to the last one allocated. You will switch between screens - with the set_term call. Note that you will also have to call - def_shell_mode and def_prog_mode on each tty yourself. - - Testing for Terminal Capabilities - - Sometimes you may want to write programs that test for the presence of - various capabilities before deciding whether to go into ncurses mode. - An easy way to do this is to call setupterm(), then use the functions - tigetflag(), tigetnum(), and tigetstr() to do your testing. - - A particularly useful case of this often comes up when you want to - test whether a given terminal type should be treated as `smart' - (cursor-addressable) or `stupid'. The right way to test this is to see - if the return value of tigetstr("cup") is non-NULL. Alternatively, you - can include the term.h file and test the value of the macro - cursor_address. - - Tuning for Speed - - Use the addchstr() family of functions for fast screen-painting of - text when you know the text doesn't contain any control characters. - Try to make attribute changes infrequent on your screens. Don't use - the immedok() option! - - Special Features of NCURSES - - The wresize() function allows you to resize a window in place. The - associated resizeterm() function simplifies the construction of - SIGWINCH handlers, for resizing all windows. - - The define_key() function allows you to define at runtime function-key - control sequences which are not in the terminal description. The - keyok() function allows you to temporarily enable or disable - interpretation of any function-key control sequence. - - The use_default_colors() function allows you to construct applications - which can use the terminal's default foreground and background colors - as an additional "default" color. Several terminal emulators support - this feature, which is based on ISO 6429. - - Ncurses supports up 16 colors, unlike SVr4 curses which defines only - 8. While most terminals which provide color allow only 8 colors, about - a quarter (including XFree86 xterm) support 16 colors. - -Compatibility with Older Versions - - Despite our best efforts, there are some differences between ncurses - and the (undocumented!) behavior of older curses implementations. - These arise from ambiguities or omissions in the documentation of the - API. - - Refresh of Overlapping Windows - - If you define two windows A and B that overlap, and then alternately - scribble on and refresh them, the changes made to the overlapping - region under historic curses versions were often not documented - precisely. - - To understand why this is a problem, remember that screen updates are - calculated between two representations of the entire display. The - documentation says that when you refresh a window, it is first copied - to to the virtual screen, and then changes are calculated to update - the physical screen (and applied to the terminal). But "copied to" is - not very specific, and subtle differences in how copying works can - produce different behaviors in the case where two overlapping windows - are each being refreshed at unpredictable intervals. - - What happens to the overlapping region depends on what wnoutrefresh() - does with its argument -- what portions of the argument window it - copies to the virtual screen. Some implementations do "change copy", - copying down only locations in the window that have changed (or been - marked changed with wtouchln() and friends). Some implementations do - "entire copy", copying all window locations to the virtual screen - whether or not they have changed. - - The ncurses library itself has not always been consistent on this - score. Due to a bug, versions 1.8.7 to 1.9.8a did entire copy. - Versions 1.8.6 and older, and versions 1.9.9 and newer, do change - copy. - - For most commercial curses implementations, it is not documented and - not known for sure (at least not to the ncurses maintainers) whether - they do change copy or entire copy. We know that System V release 3 - curses has logic in it that looks like an attempt to do change copy, - but the surrounding logic and data representations are sufficiently - complex, and our knowledge sufficiently indirect, that it's hard to - know whether this is reliable. It is not clear what the SVr4 - documentation and XSI standard intend. The XSI Curses standard barely - mentions wnoutrefresh(); the SVr4 documents seem to be describing - entire-copy, but it is possible with some effort and straining to read - them the other way. - - It might therefore be unwise to rely on either behavior in programs - that might have to be linked with other curses implementations. - Instead, you can do an explicit touchwin() before the wnoutrefresh() - call to guarantee an entire-contents copy anywhere. - - The really clean way to handle this is to use the panels library. If, - when you want a screen update, you do update_panels(), it will do all - the necessary wnoutrfresh() calls for whatever panel stacking order - you have defined. Then you can do one doupdate() and there will be a - single burst of physical I/O that will do all your updates. - - Background Erase - - If you have been using a very old versions of ncurses (1.8.7 or older) - you may be surprised by the behavior of the erase functions. In older - versions, erased areas of a window were filled with a blank modified - by the window's current attribute (as set by wattrset(), wattron(), - wattroff() and friends). - - In newer versions, this is not so. Instead, the attribute of erased - blanks is normal unless and until it is modified by the functions - bkgdset() or wbkgdset(). - - This change in behavior conforms ncurses to System V Release 4 and the - XSI Curses standard. - -XSI Curses Conformance - - The ncurses library is intended to be base-level conformant with the - XSI Curses standard from X/Open. Many extended-level features (in - fact, almost all features not directly concerned with wide characters - and internationalization) are also supported. - - One effect of XSI conformance is the change in behavior described - under "Background Erase -- Compatibility with Old Versions". - - Also, ncurses meets the XSI requirement that every macro entry point - have a corresponding function which may be linked (and will be - prototype-checked) if the macro definition is disabled with #undef. - - The Panels Library - - The ncurses library by itself provides good support for screen - displays in which the windows are tiled (non-overlapping). In the more - general case that windows may overlap, you have to use a series of - wnoutrefresh() calls followed by a doupdate(), and be careful about - the order you do the window refreshes in. It has to be bottom-upwards, - otherwise parts of windows that should be obscured will show through. - - When your interface design is such that windows may dive deeper into - the visibility stack or pop to the top at runtime, the resulting - book-keeping can be tedious and difficult to get right. Hence the - panels library. - - The panel library first appeared in AT&T System V. The version - documented here is the panel code distributed with ncurses. - -Compiling With the Panels Library - - Your panels-using modules must import the panels library declarations - with - #include <panel.h> - - and must be linked explicitly with the panels library using an -lpanel - argument. Note that they must also link the ncurses library with - -lncurses. Many linkers are two-pass and will accept either order, but - it is still good practice to put -lpanel first and -lncurses second. - -Overview of Panels - - A panel object is a window that is implicitly treated as part of a - deck including all other panel objects. The deck has an implicit - bottom-to-top visibility order. The panels library includes an update - function (analogous to refresh()) that displays all panels in the deck - in the proper order to resolve overlaps. The standard window, stdscr, - is considered below all panels. - - Details on the panels functions are available in the man pages. We'll - just hit the highlights here. - - You create a panel from a window by calling new_panel() on a window - pointer. It then becomes the top of the deck. The panel's window is - available as the value of panel_window() called with the panel pointer - as argument. - - You can delete a panel (removing it from the deck) with del_panel. - This will not deallocate the associated window; you have to do that - yourself. You can replace a panel's window with a different window by - calling replace_window. The new window may be of different size; the - panel code will re-compute all overlaps. This operation doesn't change - the panel's position in the deck. - - To move a panel's window, use move_panel(). The mvwin() function on - the panel's window isn't sufficient because it doesn't update the - panels library's representation of where the windows are. This - operation leaves the panel's depth, contents, and size unchanged. - - Two functions (top_panel(), bottom_panel()) are provided for - rearranging the deck. The first pops its argument window to the top of - the deck; the second sends it to the bottom. Either operation leaves - the panel's screen location, contents, and size unchanged. - - The function update_panels() does all the wnoutrefresh() calls needed - to prepare for doupdate() (which you must call yourself, afterwards). - - Typically, you will want to call update_panels() and doupdate() just - before accepting command input, once in each cycle of interaction with - the user. If you call update_panels() after each and every panel - write, you'll generate a lot of unnecessary refresh activity and - screen flicker. - -Panels, Input, and the Standard Screen - - You shouldn't mix wnoutrefresh() or wrefresh() operations with panels - code; this will work only if the argument window is either in the top - panel or unobscured by any other panels. - - The stsdcr window is a special case. It is considered below all - panels. Because changes to panels may obscure parts of stdscr, though, - you should call update_panels() before doupdate() even when you only - change stdscr. - - Note that wgetch automatically calls wrefresh. Therefore, before - requesting input from a panel window, you need to be sure that the - panel is totally unobscured. - - There is presently no way to display changes to one obscured panel - without repainting all panels. - -Hiding Panels - - It's possible to remove a panel from the deck temporarily; use - hide_panel for this. Use show_panel() to render it visible again. The - predicate function panel_hidden tests whether or not a panel is - hidden. - - The panel_update code ignores hidden panels. You cannot do top_panel() - or bottom_panel on a hidden panel(). Other panels operations are - applicable. - -Miscellaneous Other Facilities - - It's possible to navigate the deck using the functions panel_above() - and panel_below. Handed a panel pointer, they return the panel above - or below that panel. Handed NULL, they return the bottom-most or - top-most panel. - - Every panel has an associated user pointer, not used by the panel - code, to which you can attach application data. See the man page - documentation of set_panel_userptr() and panel_userptr for details. - - The Menu Library - - A menu is a screen display that assists the user to choose some subset - of a given set of items. The menu library is a curses extension that - supports easy programming of menu hierarchies with a uniform but - flexible interface. - - The menu library first appeared in AT&T System V. The version - documented here is the menu code distributed with ncurses. - -Compiling With the menu Library - - Your menu-using modules must import the menu library declarations with - #include <menu.h> - - and must be linked explicitly with the menus library using an -lmenu - argument. Note that they must also link the ncurses library with - -lncurses. Many linkers are two-pass and will accept either order, but - it is still good practice to put -lmenu first and -lncurses second. - -Overview of Menus - - The menus created by this library consist of collections of items - including a name string part and a description string part. To make - menus, you create groups of these items and connect them with menu - frame objects. - - The menu can then by posted, that is written to an associated window. - Actually, each menu has two associated windows; a containing window in - which the programmer can scribble titles or borders, and a subwindow - in which the menu items proper are displayed. If this subwindow is too - small to display all the items, it will be a scrollable viewport on - the collection of items. - - A menu may also be unposted (that is, undisplayed), and finally freed - to make the storage associated with it and its items available for - re-use. - - The general flow of control of a menu program looks like this: - 1. Initialize curses. - 2. Create the menu items, using new_item(). - 3. Create the menu using new_menu(). - 4. Post the menu using menu_post(). - 5. Refresh the screen. - 6. Process user requests via an input loop. - 7. Unpost the menu using menu_unpost(). - 8. Free the menu, using free_menu(). - 9. Free the items using free_item(). - 10. Terminate curses. - -Selecting items - - Menus may be multi-valued or (the default) single-valued (see the - manual page menu_opts(3x) to see how to change the default). Both - types always have a current item. - - From a single-valued menu you can read the selected value simply by - looking at the current item. From a multi-valued menu, you get the - selected set by looping through the items applying the item_value() - predicate function. Your menu-processing code can use the function - set_item_value() to flag the items in the select set. - - Menu items can be made unselectable using set_item_opts() or - item_opts_off() with the O_SELECTABLE argument. This is the only - option so far defined for menus, but it is good practice to code as - though other option bits might be on. - -Menu Display - - The menu library calculates a minimum display size for your window, - based on the following variables: - - * The number and maximum length of the menu items - * Whether the O_ROWMAJOR option is enabled - * Whether display of descriptions is enabled - * Whatever menu format may have been set by the programmer - * The length of the menu mark string used for highlighting selected - items - - The function set_menu_format() allows you to set the maximum size of - the viewport or menu page that will be used to display menu items. You - can retrieve any format associated with a menu with menu_format(). The - default format is rows=16, columns=1. - - The actual menu page may be smaller than the format size. This depends - on the item number and size and whether O_ROWMAJOR is on. This option - (on by default) causes menu items to be displayed in a `raster-scan' - pattern, so that if more than one item will fit horizontally the first - couple of items are side-by-side in the top row. The alternative is - column-major display, which tries to put the first several items in - the first column. - - As mentioned above, a menu format not large enough to allow all items - to fit on-screen will result in a menu display that is vertically - scrollable. - - You can scroll it with requests to the menu driver, which will be - described in the section on menu input handling. - - Each menu has a mark string used to visually tag selected items; see - the menu_mark(3x) manual page for details. The mark string length also - influences the menu page size. - - The function scale_menu() returns the minimum display size that the - menu code computes from all these factors. There are other menu - display attributes including a select attribute, an attribute for - selectable items, an attribute for unselectable items, and a pad - character used to separate item name text from description text. These - have reasonable defaults which the library allows you to change (see - the menu_attribs(3x) manual page. - -Menu Windows - - Each menu has, as mentioned previously, a pair of associated windows. - Both these windows are painted when the menu is posted and erased when - the menu is unposted. - - The outer or frame window is not otherwise touched by the menu - routines. It exists so the programmer can associate a title, a border, - or perhaps help text with the menu and have it properly refreshed or - erased at post/unpost time. The inner window or subwindow is where the - current menu page is displayed. - - By default, both windows are stdscr. You can set them with the - functions in menu_win(3x). - - When you call menu_post(), you write the menu to its subwindow. When - you call menu_unpost(), you erase the subwindow, However, neither of - these actually modifies the screen. To do that, call wrefresh() or - some equivalent. - -Processing Menu Input - - The main loop of your menu-processing code should call menu_driver() - repeatedly. The first argument of this routine is a menu pointer; the - second is a menu command code. You should write an input-fetching - routine that maps input characters to menu command codes, and pass its - output to menu_driver(). The menu command codes are fully documented - in menu_driver(3x). - - The simplest group of command codes is REQ_NEXT_ITEM, REQ_PREV_ITEM, - REQ_FIRST_ITEM, REQ_LAST_ITEM, REQ_UP_ITEM, REQ_DOWN_ITEM, - REQ_LEFT_ITEM, REQ_RIGHT_ITEM. These change the currently selected - item. These requests may cause scrolling of the menu page if it only - partially displayed. - - There are explicit requests for scrolling which also change the - current item (because the select location does not change, but the - item there does). These are REQ_SCR_DLINE, REQ_SCR_ULINE, - REQ_SCR_DPAGE, and REQ_SCR_UPAGE. - - The REQ_TOGGLE_ITEM selects or deselects the current item. It is for - use in multi-valued menus; if you use it with O_ONEVALUE on, you'll - get an error return (E_REQUEST_DENIED). - - Each menu has an associated pattern buffer. The menu_driver() logic - tries to accumulate printable ASCII characters passed in in that - buffer; when it matches a prefix of an item name, that item (or the - next matching item) is selected. If appending a character yields no - new match, that character is deleted from the pattern buffer, and - menu_driver() returns E_NO_MATCH. - - Some requests change the pattern buffer directly: REQ_CLEAR_PATTERN, - REQ_BACK_PATTERN, REQ_NEXT_MATCH, REQ_PREV_MATCH. The latter two are - useful when pattern buffer input matches more than one item in a - multi-valued menu. - - Each successful scroll or item navigation request clears the pattern - buffer. It is also possible to set the pattern buffer explicitly with - set_menu_pattern(). - - Finally, menu driver requests above the constant MAX_COMMAND are - considered application-specific commands. The menu_driver() code - ignores them and returns E_UNKNOWN_COMMAND. - -Miscellaneous Other Features - - Various menu options can affect the processing and visual appearance - and input processing of menus. See menu_opts(3x) for details. - - It is possible to change the current item from application code; this - is useful if you want to write your own navigation requests. It is - also possible to explicitly set the top row of the menu display. See - mitem_current(3x). If your application needs to change the menu - subwindow cursor for any reason, pos_menu_cursor() will restore it to - the correct location for continuing menu driver processing. - - It is possible to set hooks to be called at menu initialization and - wrapup time, and whenever the selected item changes. See - menu_hook(3x). - - Each item, and each menu, has an associated user pointer on which you - can hang application data. See mitem_userptr(3x) and menu_userptr(3x). - - The Forms Library - - The form library is a curses extension that supports easy programming - of on-screen forms for data entry and program control. - - The form library first appeared in AT&T System V. The version - documented here is the form code distributed with ncurses. - -Compiling With the form Library - - Your form-using modules must import the form library declarations with - #include <form.h> - - and must be linked explicitly with the forms library using an -lform - argument. Note that they must also link the ncurses library with - -lncurses. Many linkers are two-pass and will accept either order, but - it is still good practice to put -lform first and -lncurses second. - -Overview of Forms - - A form is a collection of fields; each field may be either a label - (explanatory text) or a data-entry location. Long forms may be - segmented into pages; each entry to a new page clears the screen. - - To make forms, you create groups of fields and connect them with form - frame objects; the form library makes this relatively simple. - - Once defined, a form can be posted, that is written to an associated - window. Actually, each form has two associated windows; a containing - window in which the programmer can scribble titles or borders, and a - subwindow in which the form fields proper are displayed. - - As the form user fills out the posted form, navigation and editing - keys support movement between fields, editing keys support modifying - field, and plain text adds to or changes data in a current field. The - form library allows you (the forms designer) to bind each navigation - and editing key to any keystroke accepted by curses Fields may have - validation conditions on them, so that they check input data for type - and value. The form library supplies a rich set of pre-defined field - types, and makes it relatively easy to define new ones. - - Once its transaction is completed (or aborted), a form may be unposted - (that is, undisplayed), and finally freed to make the storage - associated with it and its items available for re-use. - - The general flow of control of a form program looks like this: - 1. Initialize curses. - 2. Create the form fields, using new_field(). - 3. Create the form using new_form(). - 4. Post the form using form_post(). - 5. Refresh the screen. - 6. Process user requests via an input loop. - 7. Unpost the form using form_unpost(). - 8. Free the form, using free_form(). - 9. Free the fields using free_field(). - 10. Terminate curses. - - Note that this looks much like a menu program; the form library - handles tasks which are in many ways similar, and its interface was - obviously designed to resemble that of the menu library wherever - possible. - - In forms programs, however, the `process user requests' is somewhat - more complicated than for menus. Besides menu-like navigation - operations, the menu driver loop has to support field editing and data - validation. - -Creating and Freeing Fields and Forms - - The basic function for creating fields is new_field(): - -FIELD *new_field(int height, int width, /* new field size */ - int top, int left, /* upper left corner */ - int offscreen, /* number of offscreen rows */ - int nbuf); /* number of working buffers */ - - Menu items always occupy a single row, but forms fields may have - multiple rows. So new_field() requires you to specify a width and - height (the first two arguments, which mist both be greater than - zero). - - You must also specify the location of the field's upper left corner on - the screen (the third and fourth arguments, which must be zero or - greater). Note that these coordinates are relative to the form - subwindow, which will coincide with stdscr by default but need not be - stdscr if you've done an explicit set_form_window() call. - - The fifth argument allows you to specify a number of off-screen rows. - If this is zero, the entire field will always be displayed. If it is - nonzero, the form will be scrollable, with only one screen-full - (initially the top part) displayed at any given time. If you make a - field dynamic and grow it so it will no longer fit on the screen, the - form will become scrollable even if the offscreen argument was - initially zero. - - The forms library allocates one working buffer per field; the size of - each buffer is ((height + offscreen)*width + 1, one character for each - position in the field plus a NUL terminator. The sixth argument is the - number of additional data buffers to allocate for the field; your - application can use them for its own purposes. - -FIELD *dup_field(FIELD *field, /* field to copy */ - int top, int left); /* location of new copy */ - - The function dup_field() duplicates an existing field at a new - location. Size and buffering information are copied; some attribute - flags and status bits are not (see the form_field_new(3X) for - details). - -FIELD *link_field(FIELD *field, /* field to copy */ - int top, int left); /* location of new copy */ - - The function link_field() also duplicates an existing field at a new - location. The difference from dup_field() is that it arranges for the - new field's buffer to be shared with the old one. - - Besides the obvious use in making a field editable from two different - form pages, linked fields give you a way to hack in dynamic labels. If - you declare several fields linked to an original, and then make them - inactive, changes from the original will still be propagated to the - linked fields. - - As with duplicated fields, linked fields have attribute bits separate - from the original. - - As you might guess, all these field-allocations return NULL if the - field allocation is not possible due to an out-of-memory error or - out-of-bounds arguments. - - To connect fields to a form, use - -FORM *new_form(FIELD **fields); - - This function expects to see a NULL-terminated array of field - pointers. Said fields are connected to a newly-allocated form object; - its address is returned (or else NULL if the allocation fails). - - Note that new_field() does not copy the pointer array into private - storage; if you modify the contents of the pointer array during forms - processing, all manner of bizarre things might happen. Also note that - any given field may only be connected to one form. - - The functions free_field() and free_form are available to free field - and form objects. It is an error to attempt to free a field connected - to a form, but not vice-versa; thus, you will generally free your form - objects first. - -Fetching and Changing Field Attributes - - Each form field has a number of location and size attributes - associated with it. There are other field attributes used to control - display and editing of the field. Some (for example, the O_STATIC bit) - involve sufficient complications to be covered in sections of their - own later on. We cover the functions used to get and set several basic - attributes here. - - When a field is created, the attributes not specified by the new_field - function are copied from an invisible system default field. In - attribute-setting and -fetching functions, the argument NULL is taken - to mean this field. Changes to it persist as defaults until your forms - application terminates. - - Fetching Size and Location Data - - You can retrieve field sizes and locations through: - -int field_info(FIELD *field, /* field from which to fetch */ - int *height, *int width, /* field size */ - int *top, int *left, /* upper left corner */ - int *offscreen, /* number of offscreen rows */ - int *nbuf); /* number of working buffers */ - - This function is a sort of inverse of new_field(); instead of setting - size and location attributes of a new field, it fetches them from an - existing one. - - Changing the Field Location - - It is possible to move a field's location on the screen: - -int move_field(FIELD *field, /* field to alter */ - int top, int left); /* new upper-left corner */ - - You can, of course. query the current location through field_info(). - - The Justification Attribute - - One-line fields may be unjustified, justified right, justified left, - or centered. Here is how you manipulate this attribute: - -int set_field_just(FIELD *field, /* field to alter */ - int justmode); /* mode to set */ - -int field_just(FIELD *field); /* fetch mode of field */ - - The mode values accepted and returned by this functions are - preprocessor macros NO_JUSTIFICATION, JUSTIFY_RIGHT, JUSTIFY_LEFT, or - JUSTIFY_CENTER. - - Field Display Attributes - - For each field, you can set a foreground attribute for entered - characters, a background attribute for the entire field, and a pad - character for the unfilled portion of the field. You can also control - pagination of the form. - - This group of four field attributes controls the visual appearance of - the field on the screen, without affecting in any way the data in the - field buffer. - -int set_field_fore(FIELD *field, /* field to alter */ - chtype attr); /* attribute to set */ - -chtype field_fore(FIELD *field); /* field to query */ - -int set_field_back(FIELD *field, /* field to alter */ - chtype attr); /* attribute to set */ - -chtype field_back(FIELD *field); /* field to query */ - -int set_field_pad(FIELD *field, /* field to alter */ - int pad); /* pad character to set */ - -chtype field_pad(FIELD *field); - -int set_new_page(FIELD *field, /* field to alter */ - int flag); /* TRUE to force new page */ - -chtype new_page(FIELD *field); /* field to query */ - - The attributes set and returned by the first four functions are normal - curses(3x) display attribute values (A_STANDOUT, A_BOLD, A_REVERSE - etc). The page bit of a field controls whether it is displayed at the - start of a new form screen. - - Field Option Bits - - There is also a large collection of field option bits you can set to - control various aspects of forms processing. You can manipulate them - with these functions: -int set_field_opts(FIELD *field, /* field to alter */ - int attr); /* attribute to set */ - -int field_opts_on(FIELD *field, /* field to alter */ - int attr); /* attributes to turn on */ - -int field_opts_off(FIELD *field, /* field to alter */ - int attr); /* attributes to turn off */ - -int field_opts(FIELD *field); /* field to query */ - - By default, all options are on. Here are the available option bits: - - O_VISIBLE - Controls whether the field is visible on the screen. Can be - used during form processing to hide or pop up fields depending - on the value of parent fields. - - O_ACTIVE - Controls whether the field is active during forms processing - (i.e. visited by form navigation keys). Can be used to make - labels or derived fields with buffer values alterable by the - forms application, not the user. - - O_PUBLIC - Controls whether data is displayed during field entry. If this - option is turned off on a field, the library will accept and - edit data in that field, but it will not be displayed and the - visible field cursor will not move. You can turn off the - O_PUBLIC bit to define password fields. - - O_EDIT - Controls whether the field's data can be modified. When this - option is off, all editing requests except REQ_PREV_CHOICE and - REQ_NEXT_CHOICE will fail. Such read-only fields may be useful - for help messages. - - O_WRAP - Controls word-wrapping in multi-line fields. Normally, when any - character of a (blank-separated) word reaches the end of the - current line, the entire word is wrapped to the next line - (assuming there is one). When this option is off, the word will - be split across the line break. - - O_BLANK - Controls field blanking. When this option is on, entering a - character at the first field position erases the entire field - (except for the just-entered character). - - O_AUTOSKIP - Controls automatic skip to next field when this one fills. - Normally, when the forms user tries to type more data into a - field than will fit, the editing location jumps to next field. - When this option is off, the user's cursor will hang at the end - of the field. This option is ignored in dynamic fields that - have not reached their size limit. - - O_NULLOK - Controls whether validation is applied to blank fields. - Normally, it is not; the user can leave a field blank without - invoking the usual validation check on exit. If this option is - off on a field, exit from it will invoke a validation check. - - O_PASSOK - Controls whether validation occurs on every exit, or only after - the field is modified. Normally the latter is true. Setting - O_PASSOK may be useful if your field's validation function may - change during forms processing. - - O_STATIC - Controls whether the field is fixed to its initial dimensions. - If you turn this off, the field becomes dynamic and will - stretch to fit entered data. - - A field's options cannot be changed while the field is currently - selected. However, options may be changed on posted fields that are - not current. - - The option values are bit-masks and can be composed with logical-or in - the obvious way. - -Field Status - - Every field has a status flag, which is set to FALSE when the field is - created and TRUE when the value in field buffer 0 changes. This flag - can be queried and set directly: - -int set_field_status(FIELD *field, /* field to alter */ - int status); /* mode to set */ - -int field_status(FIELD *field); /* fetch mode of field */ - - Setting this flag under program control can be useful if you use the - same form repeatedly, looking for modified fields each time. - - Calling field_status() on a field not currently selected for input - will return a correct value. Calling field_status() on a field that is - currently selected for input may not necessarily give a correct field - status value, because entered data isn't necessarily copied to buffer - zero before the exit validation check. To guarantee that the returned - status value reflects reality, call field_status() either (1) in the - field's exit validation check routine, (2) from the field's or form's - initialization or termination hooks, or (3) just after a - REQ_VALIDATION request has been processed by the forms driver. - -Field User Pointer - - Each field structure contains one character pointer slot that is not - used by the forms library. It is intended to be used by applications - to store private per-field data. You can manipulate it with: -int set_field_userptr(FIELD *field, /* field to alter */ - char *userptr); /* mode to set */ - -char *field_userptr(FIELD *field); /* fetch mode of field */ - - (Properly, this user pointer field ought to have (void *) type. The - (char *) type is retained for System V compatibility.) - - It is valid to set the user pointer of the default field (with a - set_field_userptr() call passed a NULL field pointer.) When a new - field is created, the default-field user pointer is copied to - initialize the new field's user pointer. - -Variable-Sized Fields - - Normally, a field is fixed at the size specified for it at creation - time. If, however, you turn off its O_STATIC bit, it becomes dynamic - and will automatically resize itself to accommodate data as it is - entered. If the field has extra buffers associated with it, they will - grow right along with the main input buffer. - - A one-line dynamic field will have a fixed height (1) but variable - width, scrolling horizontally to display data within the field area as - originally dimensioned and located. A multi-line dynamic field will - have a fixed width, but variable height (number of rows), scrolling - vertically to display data within the field area as originally - dimensioned and located. - - Normally, a dynamic field is allowed to grow without limit. But it is - possible to set an upper limit on the size of a dynamic field. You do - it with this function: - -int set_max_field(FIELD *field, /* field to alter (may not be NULL) */ - int max_size); /* upper limit on field size */ - - If the field is one-line, max_size is taken to be a column size limit; - if it is multi-line, it is taken to be a line size limit. To disable - any limit, use an argument of zero. The growth limit can be changed - whether or not the O_STATIC bit is on, but has no effect until it is. - - The following properties of a field change when it becomes dynamic: - * If there is no growth limit, there is no final position of the - field; therefore O_AUTOSKIP and O_NL_OVERLOAD are ignored. - * Field justification will be ignored (though whatever justification - is set up will be retained internally and can be queried). - * The dup_field() and link_field() calls copy dynamic-buffer sizes. - If the O_STATIC option is set on one of a collection of links, - buffer resizing will occur only when the field is edited through - that link. - * The call field_info() will retrieve the original static size of - the field; use dynamic_field_info() to get the actual dynamic - size. - -Field Validation - - By default, a field will accept any data that will fit in its input - buffer. However, it is possible to attach a validation type to a - field. If you do this, any attempt to leave the field while it - contains data that doesn't match the validation type will fail. Some - validation types also have a character-validity check for each time a - character is entered in the field. - - A field's validation check (if any) is not called when - set_field_buffer() modifies the input buffer, nor when that buffer is - changed through a linked field. - - The form library provides a rich set of pre-defined validation types, - and gives you the capability to define custom ones of your own. You - can examine and change field validation attributes with the following - functions: - -int set_field_type(FIELD *field, /* field to alter */ - FIELDTYPE *ftype, /* type to associate */ - ...); /* additional arguments*/ - -FIELDTYPE *field_type(FIELD *field); /* field to query */ - - The validation type of a field is considered an attribute of the - field. As with other field attributes, Also, doing set_field_type() - with a NULL field default will change the system default for - validation of newly-created fields. - - Here are the pre-defined validation types: - - TYPE_ALPHA - - This field type accepts alphabetic data; no blanks, no digits, no - special characters (this is checked at character-entry time). It is - set up with: - -int set_field_type(FIELD *field, /* field to alter */ - TYPE_ALPHA, /* type to associate */ - int width); /* maximum width of field */ - - The width argument sets a minimum width of data. Typically you'll want - to set this to the field width; if it's greater than the field width, - the validation check will always fail. A minimum width of zero makes - field completion optional. - - TYPE_ALNUM - - This field type accepts alphabetic data and digits; no blanks, no - special characters (this is checked at character-entry time). It is - set up with: - -int set_field_type(FIELD *field, /* field to alter */ - TYPE_ALNUM, /* type to associate */ - int width); /* maximum width of field */ - - The width argument sets a minimum width of data. As with TYPE_ALPHA, - typically you'll want to set this to the field width; if it's greater - than the field width, the validation check will always fail. A minimum - width of zero makes field completion optional. - - TYPE_ENUM - - This type allows you to restrict a field's values to be among a - specified set of string values (for example, the two-letter postal - codes for U.S. states). It is set up with: - -int set_field_type(FIELD *field, /* field to alter */ - TYPE_ENUM, /* type to associate */ - char **valuelist; /* list of possible values */ - int checkcase; /* case-sensitive? */ - int checkunique); /* must specify uniquely? */ - - The valuelist parameter must point at a NULL-terminated list of valid - strings. The checkcase argument, if true, makes comparison with the - string case-sensitive. - - When the user exits a TYPE_ENUM field, the validation procedure tries - to complete the data in the buffer to a valid entry. If a complete - choice string has been entered, it is of course valid. But it is also - possible to enter a prefix of a valid string and have it completed for - you. - - By default, if you enter such a prefix and it matches more than one - value in the string list, the prefix will be completed to the first - matching value. But the checkunique argument, if true, requires prefix - matches to be unique in order to be valid. - - The REQ_NEXT_CHOICE and REQ_PREV_CHOICE input requests can be - particularly useful with these fields. - - TYPE_INTEGER - - This field type accepts an integer. It is set up as follows: - -int set_field_type(FIELD *field, /* field to alter */ - TYPE_INTEGER, /* type to associate */ - int padding, /* # places to zero-pad to */ - int vmin, int vmax); /* valid range */ - - Valid characters consist of an optional leading minus and digits. The - range check is performed on exit. If the range maximum is less than or - equal to the minimum, the range is ignored. - - If the value passes its range check, it is padded with as many leading - zero digits as necessary to meet the padding argument. - - A TYPE_INTEGER value buffer can conveniently be interpreted with the C - library function atoi(3). - - TYPE_NUMERIC - - This field type accepts a decimal number. It is set up as follows: - -int set_field_type(FIELD *field, /* field to alter */ - TYPE_NUMERIC, /* type to associate */ - int padding, /* # places of precision */ - double vmin, double vmax); /* valid range */ - - Valid characters consist of an optional leading minus and digits. - possibly including a decimal point. If your system supports locale's, - the decimal point character used must be the one defined by your - locale. The range check is performed on exit. If the range maximum is - less than or equal to the minimum, the range is ignored. - - If the value passes its range check, it is padded with as many - trailing zero digits as necessary to meet the padding argument. - - A TYPE_NUMERIC value buffer can conveniently be interpreted with the C - library function atof(3). - - TYPE_REGEXP - - This field type accepts data matching a regular expression. It is set - up as follows: - -int set_field_type(FIELD *field, /* field to alter */ - TYPE_REGEXP, /* type to associate */ - char *regexp); /* expression to match */ - - The syntax for regular expressions is that of regcomp(3). The check - for regular-expression match is performed on exit. - -Direct Field Buffer Manipulation - - The chief attribute of a field is its buffer contents. When a form has - been completed, your application usually needs to know the state of - each field buffer. You can find this out with: - -char *field_buffer(FIELD *field, /* field to query */ - int bufindex); /* number of buffer to query */ - - Normally, the state of the zero-numbered buffer for each field is set - by the user's editing actions on that field. It's sometimes useful to - be able to set the value of the zero-numbered (or some other) buffer - from your application: -int set_field_buffer(FIELD *field, /* field to alter */ - int bufindex, /* number of buffer to alter */ - char *value); /* string value to set */ - - If the field is not large enough and cannot be resized to a - sufficiently large size to contain the specified value, the value will - be truncated to fit. - - Calling field_buffer() with a null field pointer will raise an error. - Calling field_buffer() on a field not currently selected for input - will return a correct value. Calling field_buffer() on a field that is - currently selected for input may not necessarily give a correct field - buffer value, because entered data isn't necessarily copied to buffer - zero before the exit validation check. To guarantee that the returned - buffer value reflects on-screen reality, call field_buffer() either - (1) in the field's exit validation check routine, (2) from the field's - or form's initialization or termination hooks, or (3) just after a - REQ_VALIDATION request has been processed by the forms driver. - -Attributes of Forms - - As with field attributes, form attributes inherit a default from a - system default form structure. These defaults can be queried or set by - of these functions using a form-pointer argument of NULL. - - The principal attribute of a form is its field list. You can query and - change this list with: - -int set_form_fields(FORM *form, /* form to alter */ - FIELD **fields); /* fields to connect */ - -char *form_fields(FORM *form); /* fetch fields of form */ - -int field_count(FORM *form); /* count connect fields */ - - The second argument of set_form_fields() may be a NULL-terminated - field pointer array like the one required by new_form(). In that case, - the old fields of the form are disconnected but not freed (and - eligible to be connected to other forms), then the new fields are - connected. - - It may also be null, in which case the old fields are disconnected - (and not freed) but no new ones are connected. - - The field_count() function simply counts the number of fields - connected to a given from. It returns -1 if the form-pointer argument - is NULL. - -Control of Form Display - - In the overview section, you saw that to display a form you normally - start by defining its size (and fields), posting it, and refreshing - the screen. There is an hidden step before posting, which is the - association of the form with a frame window (actually, a pair of - windows) within which it will be displayed. By default, the forms - library associates every form with the full-screen window stdscr. - - By making this step explicit, you can associate a form with a declared - frame window on your screen display. This can be useful if you want to - adapt the form display to different screen sizes, dynamically tile - forms on the screen, or use a form as part of an interface layout - managed by panels. - - The two windows associated with each form have the same functions as - their analogues in the menu library. Both these windows are painted - when the form is posted and erased when the form is unposted. - - The outer or frame window is not otherwise touched by the form - routines. It exists so the programmer can associate a title, a border, - or perhaps help text with the form and have it properly refreshed or - erased at post/unpost time. The inner window or subwindow is where the - current form page is actually displayed. - - In order to declare your own frame window for a form, you'll need to - know the size of the form's bounding rectangle. You can get this - information with: - -int scale_form(FORM *form, /* form to query */ - int *rows, /* form rows */ - int *cols); /* form cols */ - - The form dimensions are passed back in the locations pointed to by the - arguments. Once you have this information, you can use it to declare - of windows, then use one of these functions: -int set_form_win(FORM *form, /* form to alter */ - WINDOW *win); /* frame window to connect */ - -WINDOW *form_win(FORM *form); /* fetch frame window of form */ - -int set_form_sub(FORM *form, /* form to alter */ - WINDOW *win); /* form subwindow to connect */ - -WINDOW *form_sub(FORM *form); /* fetch form subwindow of form */ - - Note that curses operations, including refresh(), on the form, should - be done on the frame window, not the form subwindow. - - It is possible to check from your application whether all of a - scrollable field is actually displayed within the menu subwindow. Use - these functions: - -int data_ahead(FORM *form); /* form to be queried */ - -int data_behind(FORM *form); /* form to be queried */ - - The function data_ahead() returns TRUE if (a) the current field is - one-line and has undisplayed data off to the right, (b) the current - field is multi-line and there is data off-screen below it. - - The function data_behind() returns TRUE if the first (upper left hand) - character position is off-screen (not being displayed). - - Finally, there is a function to restore the form window's cursor to - the value expected by the forms driver: - -int pos_form_cursor(FORM *) /* form to be queried */ - - If your application changes the form window cursor, call this function - before handing control back to the forms driver in order to - re-synchronize it. - -Input Processing in the Forms Driver - - The function form_driver() handles virtualized input requests for form - navigation, editing, and validation requests, just as menu_driver does - for menus (see the section on menu input handling). - -int form_driver(FORM *form, /* form to pass input to */ - int request); /* form request code */ - - Your input virtualization function needs to take input and then - convert it to either an alphanumeric character (which is treated as - data to be entered in the currently-selected field), or a forms - processing request. - - The forms driver provides hooks (through input-validation and - field-termination functions) with which your application code can - check that the input taken by the driver matched what was expected. - - Page Navigation Requests - - These requests cause page-level moves through the form, triggering - display of a new form screen. - - REQ_NEXT_PAGE - Move to the next form page. - - REQ_PREV_PAGE - Move to the previous form page. - - REQ_FIRST_PAGE - Move to the first form page. - - REQ_LAST_PAGE - Move to the last form page. - - These requests treat the list as cyclic; that is, REQ_NEXT_PAGE from - the last page goes to the first, and REQ_PREV_PAGE from the first page - goes to the last. - - Inter-Field Navigation Requests - - These requests handle navigation between fields on the same page. - - REQ_NEXT_FIELD - Move to next field. - - REQ_PREV_FIELD - Move to previous field. - - REQ_FIRST_FIELD - Move to the first field. - - REQ_LAST_FIELD - Move to the last field. - - REQ_SNEXT_FIELD - Move to sorted next field. - - REQ_SPREV_FIELD - Move to sorted previous field. - - REQ_SFIRST_FIELD - Move to the sorted first field. - - REQ_SLAST_FIELD - Move to the sorted last field. - - REQ_LEFT_FIELD - Move left to field. - - REQ_RIGHT_FIELD - Move right to field. - - REQ_UP_FIELD - Move up to field. - - REQ_DOWN_FIELD - Move down to field. - - These requests treat the list of fields on a page as cyclic; that is, - REQ_NEXT_FIELD from the last field goes to the first, and - REQ_PREV_FIELD from the first field goes to the last. The order of the - fields for these (and the REQ_FIRST_FIELD and REQ_LAST_FIELD requests) - is simply the order of the field pointers in the form array (as set up - by new_form() or set_form_fields() - - It is also possible to traverse the fields as if they had been sorted - in screen-position order, so the sequence goes left-to-right and - top-to-bottom. To do this, use the second group of four - sorted-movement requests. - - Finally, it is possible to move between fields using visual directions - up, down, right, and left. To accomplish this, use the third group of - four requests. Note, however, that the position of a form for purposes - of these requests is its upper-left corner. - - For example, suppose you have a multi-line field B, and two - single-line fields A and C on the same line with B, with A to the left - of B and C to the right of B. A REQ_MOVE_RIGHT from A will go to B - only if A, B, and C all share the same first line; otherwise it will - skip over B to C. - - Intra-Field Navigation Requests - - These requests drive movement of the edit cursor within the currently - selected field. - - REQ_NEXT_CHAR - Move to next character. - - REQ_PREV_CHAR - Move to previous character. - - REQ_NEXT_LINE - Move to next line. - - REQ_PREV_LINE - Move to previous line. - - REQ_NEXT_WORD - Move to next word. - - REQ_PREV_WORD - Move to previous word. - - REQ_BEG_FIELD - Move to beginning of field. - - REQ_END_FIELD - Move to end of field. - - REQ_BEG_LINE - Move to beginning of line. - - REQ_END_LINE - Move to end of line. - - REQ_LEFT_CHAR - Move left in field. - - REQ_RIGHT_CHAR - Move right in field. - - REQ_UP_CHAR - Move up in field. - - REQ_DOWN_CHAR - Move down in field. - - Each word is separated from the previous and next characters by - whitespace. The commands to move to beginning and end of line or field - look for the first or last non-pad character in their ranges. - - Scrolling Requests - - Fields that are dynamic and have grown and fields explicitly created - with offscreen rows are scrollable. One-line fields scroll - horizontally; multi-line fields scroll vertically. Most scrolling is - triggered by editing and intra-field movement (the library scrolls the - field to keep the cursor visible). It is possible to explicitly - request scrolling with the following requests: - - REQ_SCR_FLINE - Scroll vertically forward a line. - - REQ_SCR_BLINE - Scroll vertically backward a line. - - REQ_SCR_FPAGE - Scroll vertically forward a page. - - REQ_SCR_BPAGE - Scroll vertically backward a page. - - REQ_SCR_FHPAGE - Scroll vertically forward half a page. - - REQ_SCR_BHPAGE - Scroll vertically backward half a page. - - REQ_SCR_FCHAR - Scroll horizontally forward a character. - - REQ_SCR_BCHAR - Scroll horizontally backward a character. - - REQ_SCR_HFLINE - Scroll horizontally one field width forward. - - REQ_SCR_HBLINE - Scroll horizontally one field width backward. - - REQ_SCR_HFHALF - Scroll horizontally one half field width forward. - - REQ_SCR_HBHALF - Scroll horizontally one half field width backward. - - For scrolling purposes, a page of a field is the height of its visible - part. - - Editing Requests - - When you pass the forms driver an ASCII character, it is treated as a - request to add the character to the field's data buffer. Whether this - is an insertion or a replacement depends on the field's edit mode - (insertion is the default. - - The following requests support editing the field and changing the edit - mode: - - REQ_INS_MODE - Set insertion mode. - - REQ_OVL_MODE - Set overlay mode. - - REQ_NEW_LINE - New line request (see below for explanation). - - REQ_INS_CHAR - Insert space at character location. - - REQ_INS_LINE - Insert blank line at character location. - - REQ_DEL_CHAR - Delete character at cursor. - - REQ_DEL_PREV - Delete previous word at cursor. - - REQ_DEL_LINE - Delete line at cursor. - - REQ_DEL_WORD - Delete word at cursor. - - REQ_CLR_EOL - Clear to end of line. - - REQ_CLR_EOF - Clear to end of field. - - REQ_CLEAR_FIELD - Clear entire field. - - The behavior of the REQ_NEW_LINE and REQ_DEL_PREV requests is - complicated and partly controlled by a pair of forms options. The - special cases are triggered when the cursor is at the beginning of a - field, or on the last line of the field. - - First, we consider REQ_NEW_LINE: - - The normal behavior of REQ_NEW_LINE in insert mode is to break the - current line at the position of the edit cursor, inserting the portion - of the current line after the cursor as a new line following the - current and moving the cursor to the beginning of that new line (you - may think of this as inserting a newline in the field buffer). - - The normal behavior of REQ_NEW_LINE in overlay mode is to clear the - current line from the position of the edit cursor to end of line. The - cursor is then moved to the beginning of the next line. - - However, REQ_NEW_LINE at the beginning of a field, or on the last line - of a field, instead does a REQ_NEXT_FIELD. O_NL_OVERLOAD option is - off, this special action is disabled. - - Now, let us consider REQ_DEL_PREV: - - The normal behavior of REQ_DEL_PREV is to delete the previous - character. If insert mode is on, and the cursor is at the start of a - line, and the text on that line will fit on the previous one, it - instead appends the contents of the current line to the previous one - and deletes the current line (you may think of this as deleting a - newline from the field buffer). - - However, REQ_DEL_PREV at the beginning of a field is instead treated - as a REQ_PREV_FIELD. - - If the O_BS_OVERLOAD option is off, this special action is disabled - and the forms driver just returns E_REQUEST_DENIED. - - See Form Options for discussion of how to set and clear the overload - options. - - Order Requests - - If the type of your field is ordered, and has associated functions for - getting the next and previous values of the type from a given value, - there are requests that can fetch that value into the field buffer: - - REQ_NEXT_CHOICE - Place the successor value of the current value in the buffer. - - REQ_PREV_CHOICE - Place the predecessor value of the current value in the buffer. - - Of the built-in field types, only TYPE_ENUM has built-in successor and - predecessor functions. When you define a field type of your own (see - Custom Validation Types), you can associate our own ordering - functions. - - Application Commands - - Form requests are represented as integers above the curses value - greater than KEY_MAX and less than or equal to the constant - MAX_COMMAND. If your input-virtualization routine returns a value - above MAX_COMMAND, the forms driver will ignore it. - -Field Change Hooks - - It is possible to set function hooks to be executed whenever the - current field or form changes. Here are the functions that support - this: - -typedef void (*HOOK)(); /* pointer to function returning void */ - -int set_form_init(FORM *form, /* form to alter */ - HOOK hook); /* initialization hook */ - -HOOK form_init(FORM *form); /* form to query */ - -int set_form_term(FORM *form, /* form to alter */ - HOOK hook); /* termination hook */ - -HOOK form_term(FORM *form); /* form to query */ - -int set_field_init(FORM *form, /* form to alter */ - HOOK hook); /* initialization hook */ - -HOOK field_init(FORM *form); /* form to query */ - -int set_field_term(FORM *form, /* form to alter */ - HOOK hook); /* termination hook */ - -HOOK field_term(FORM *form); /* form to query */ - - These functions allow you to either set or query four different hooks. - In each of the set functions, the second argument should be the - address of a hook function. These functions differ only in the timing - of the hook call. - - form_init - This hook is called when the form is posted; also, just after - each page change operation. - - field_init - This hook is called when the form is posted; also, just after - each field change - - field_term - This hook is called just after field validation; that is, just - before the field is altered. It is also called when the form is - unposted. - - form_term - This hook is called when the form is unposted; also, just - before each page change operation. - - Calls to these hooks may be triggered - 1. When user editing requests are processed by the forms driver - 2. When the current page is changed by set_current_field() call - 3. When the current field is changed by a set_form_page() call - - See Field Change Commands for discussion of the latter two cases. - - You can set a default hook for all fields by passing one of the set - functions a NULL first argument. - - You can disable any of these hooks by (re)setting them to NULL, the - default value. - -Field Change Commands - - Normally, navigation through the form will be driven by the user's - input requests. But sometimes it is useful to be able to move the - focus for editing and viewing under control of your application, or - ask which field it currently is in. The following functions help you - accomplish this: - -int set_current_field(FORM *form, /* form to alter */ - FIELD *field); /* field to shift to */ - -FIELD *current_field(FORM *form); /* form to query */ - -int field_index(FORM *form, /* form to query */ - FIELD *field); /* field to get index of */ - - The function field_index() returns the index of the given field in the - given form's field array (the array passed to new_form() or - set_form_fields()). - - The initial current field of a form is the first active field on the - first page. The function set_form_fields() resets this. - - It is also possible to move around by pages. - -int set_form_page(FORM *form, /* form to alter */ - int page); /* page to go to (0-origin) */ - -int form_page(FORM *form); /* return form's current page */ - - The initial page of a newly-created form is 0. The function - set_form_fields() resets this. - -Form Options - - Like fields, forms may have control option bits. They can be changed - or queried with these functions: - -int set_form_opts(FORM *form, /* form to alter */ - int attr); /* attribute to set */ - -int form_opts_on(FORM *form, /* form to alter */ - int attr); /* attributes to turn on */ - -int form_opts_off(FORM *form, /* form to alter */ - int attr); /* attributes to turn off */ - -int form_opts(FORM *form); /* form to query */ - - By default, all options are on. Here are the available option bits: - - O_NL_OVERLOAD - Enable overloading of REQ_NEW_LINE as described in Editing - Requests. The value of this option is ignored on dynamic fields - that have not reached their size limit; these have no last - line, so the circumstances for triggering a REQ_NEXT_FIELD - never arise. - - O_BS_OVERLOAD - Enable overloading of REQ_DEL_PREV as described in Editing - Requests. - - The option values are bit-masks and can be composed with logical-or in - the obvious way. - -Custom Validation Types - - The form library gives you the capability to define custom validation - types of your own. Further, the optional additional arguments of - set_field_type effectively allow you to parameterize validation types. - Most of the complications in the validation-type interface have to do - with the handling of the additional arguments within custom validation - functions. - - Union Types - - The simplest way to create a custom data type is to compose it from - two preexisting ones: - -FIELD *link_fieldtype(FIELDTYPE *type1, - FIELDTYPE *type2); - - This function creates a field type that will accept any of the values - legal for either of its argument field types (which may be either - predefined or programmer-defined). If a set_field_type() call later - requires arguments, the new composite type expects all arguments for - the first type, than all arguments for the second. Order functions - (see Order Requests) associated with the component types will work on - the composite; what it does is check the validation function for the - first type, then for the second, to figure what type the buffer - contents should be treated as. - - New Field Types - - To create a field type from scratch, you need to specify one or both - of the following things: - - * A character-validation function, to check each character as it is - entered. - * A field-validation function to be applied on exit from the field. - - Here's how you do that: - -typedef int (*HOOK)(); /* pointer to function returning int */ - -FIELDTYPE *new_fieldtype(HOOK f_validate, /* field validator */ - HOOK c_validate) /* character validator */ - - -int free_fieldtype(FIELDTYPE *ftype); /* type to free */ - - At least one of the arguments of new_fieldtype() must be non-NULL. The - forms driver will automatically call the new type's validation - functions at appropriate points in processing a field of the new type. - - The function free_fieldtype() deallocates the argument fieldtype, - freeing all storage associated with it. - - Normally, a field validator is called when the user attempts to leave - the field. Its first argument is a field pointer, from which it can - get to field buffer 0 and test it. If the function returns TRUE, the - operation succeeds; if it returns FALSE, the edit cursor stays in the - field. - - A character validator gets the character passed in as a first - argument. It too should return TRUE if the character is valid, FALSE - otherwise. - - Validation Function Arguments - - Your field- and character- validation functions will be passed a - second argument as well. This second argument is the address of a - structure (which we'll call a pile) built from any of the - field-type-specific arguments passed to set_field_type(). If no such - arguments are defined for the field type, this pile pointer argument - will be NULL. - - In order to arrange for such arguments to be passed to your validation - functions, you must associate a small set of storage-management - functions with the type. The forms driver will use these to synthesize - a pile from the trailing arguments of each set_field_type() argument, - and a pointer to the pile will be passed to the validation functions. - - Here is how you make the association: - -typedef char *(*PTRHOOK)(); /* pointer to function returning (char *) */ -typedef void (*VOIDHOOK)(); /* pointer to function returning void */ - -int set_fieldtype_arg(FIELDTYPE *type, /* type to alter */ - PTRHOOK make_str, /* make structure from args */ - PTRHOOK copy_str, /* make copy of structure */ - VOIDHOOK free_str); /* free structure storage */ - - Here is how the storage-management hooks are used: - - make_str - This function is called by set_field_type(). It gets one - argument, a va_list of the type-specific arguments passed to - set_field_type(). It is expected to return a pile pointer to a - data structure that encapsulates those arguments. - - copy_str - This function is called by form library functions that allocate - new field instances. It is expected to take a pile pointer, - copy the pile to allocated storage, and return the address of - the pile copy. - - free_str - This function is called by field- and type-deallocation - routines in the library. It takes a pile pointer argument, and - is expected to free the storage of that pile. - - The make_str and copy_str functions may return NULL to signal - allocation failure. The library routines will that call them will - return error indication when this happens. Thus, your validation - functions should never see a NULL file pointer and need not check - specially for it. - - Order Functions For Custom Types - - Some custom field types are simply ordered in the same well-defined - way that TYPE_ENUM is. For such types, it is possible to define - successor and predecessor functions to support the REQ_NEXT_CHOICE and - REQ_PREV_CHOICE requests. Here's how: - -typedef int (*INTHOOK)(); /* pointer to function returning int */ - -int set_fieldtype_arg(FIELDTYPE *type, /* type to alter */ - INTHOOK succ, /* get successor value */ - INTHOOK pred); /* get predecessor value */ - - The successor and predecessor arguments will each be passed two - arguments; a field pointer, and a pile pointer (as for the validation - functions). They are expected to use the function field_buffer() to - read the current value, and set_field_buffer() on buffer 0 to set the - next or previous value. Either hook may return TRUE to indicate - success (a legal next or previous value was set) or FALSE to indicate - failure. - - Avoiding Problems - - The interface for defining custom types is complicated and tricky. - Rather than attempting to create a custom type entirely from scratch, - you should start by studying the library source code for whichever of - the pre-defined types seems to be closest to what you want. - - Use that code as a model, and evolve it towards what you really want. - You will avoid many problems and annoyances that way. The code in the - ncurses library has been specifically exempted from the package - copyright to support this. - - If your custom type defines order functions, have do something - intuitive with a blank field. A useful convention is to make the - successor of a blank field the types minimum value, and its - predecessor the maximum. diff --git a/contrib/ncurses/misc/ncurses-intro.html b/contrib/ncurses/misc/ncurses-intro.html deleted file mode 100644 index d01c65e6e52d..000000000000 --- a/contrib/ncurses/misc/ncurses-intro.html +++ /dev/null @@ -1,2682 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 3.0//EN"> -<!-- - $Id: ncurses-intro.html,v 1.31 1999/05/16 17:02:31 juergen Exp $ ---> -<HTML> -<HEAD> -<TITLE>Writing Programs with NCURSES</TITLE> -<link rev="made" href="mailto:bugs-ncurses@gnu.org"> -</HEAD> -<BODY> - -<H1>Writing Programs with NCURSES</H1> - -<BLOCKQUOTE> -by Eric S. Raymond and Zeyd M. Ben-Halim<BR> -updates since release 1.9.9e by Thomas Dickey -</BLOCKQUOTE> - -<H1>Contents</H1> -<UL> -<LI><A HREF="#introduction">Introduction</A> -<UL> -<LI><A HREF="#history">A Brief History of Curses</A> -<LI><A HREF="#scope">Scope of This Document</A> -<LI><A HREF="#terminology">Terminology</A> -</UL> -<LI><A HREF="#curses">The Curses Library</A> -<UL> -<LI><A HREF="#overview">An Overview of Curses</A> -<UL> -<LI><A HREF="#compiling">Compiling Programs using Curses</A> -<LI><A HREF="#updating">Updating the Screen</A> -<LI><A HREF="#stdscr">Standard Windows and Function Naming Conventions</A> -<LI><A HREF="#variables">Variables</A> -</UL> -<LI><A HREF="#using">Using the Library</A> -<UL> -<LI><A HREF="#starting">Starting up</A> -<LI><A HREF="#output">Output</A> -<LI><A HREF="#input">Input</A> -<LI><A HREF="#formschars">Using Forms Characters</A> -<LI><A HREF="#attributes">Character Attributes and Color</A> -<LI><A HREF="#mouse">Mouse Interfacing</A> -<LI><A HREF="#finishing">Finishing Up</A> -</UL> -<LI><A HREF="#functions">Function Descriptions</A> -<UL> -<LI><A HREF="#init">Initialization and Wrapup</A> -<LI><A HREF="#flush">Causing Output to the Terminal</A> -<LI><A HREF="#lowlevel">Low-Level Capability Access</A> -<LI><A HREF="#debugging">Debugging</A> -</UL> -<LI><A HREF="#hints">Hints, Tips, and Tricks</A> -<UL> -<LI><A HREF="#caution">Some Notes of Caution</A> -<LI><A HREF="#leaving">Temporarily Leaving ncurses Mode</A> -<LI><A HREF="#xterm">Using <CODE>ncurses</CODE> under <CODE>xterm</CODE></A> -<LI><A HREF="#screens">Handling Multiple Terminal Screens</A> -<LI><A HREF="#testing">Testing for Terminal Capabilities</A> -<LI><A HREF="#tuning">Tuning for Speed</A> -<LI><A HREF="#special">Special Features of <CODE>ncurses</CODE></A> -</UL> -<LI><A HREF="#compat">Compatibility with Older Versions</A> -<UL> -<LI><A HREF="#refbug">Refresh of Overlapping Windows</A> -<LI><A HREF="#backbug">Background Erase</A> -</UL> -<LI><A HREF="#xsifuncs">XSI Curses Conformance</A> -</UL> -<LI><A HREF="#panels">The Panels Library</A> -<UL> -<LI><A HREF="#pcompile">Compiling With the Panels Library</A> -<LI><A HREF="#poverview">Overview of Panels</A> -<LI><A HREF="#pstdscr">Panels, Input, and the Standard Screen</A> -<LI><A HREF="#hiding">Hiding Panels</A> -<LI><A HREF="#pmisc">Miscellaneous Other Facilities</A> -</UL> -<LI><A HREF="#menu">The Menu Library</A> -<UL> -<LI><A HREF="#mcompile">Compiling with the menu Library</A> -<LI><A HREF="#moverview">Overview of Menus</A> -<LI><A HREF="#mselect">Selecting items</A> -<LI><A HREF="#mdisplay">Menu Display</A> -<LI><A HREF="#mwindows">Menu Windows</A> -<LI><A HREF="#minput">Processing Menu Input</A> -<LI><A HREF="#mmisc">Miscellaneous Other Features</A> -</UL> -<LI><A HREF="#form">The Forms Library</A> -<UL> -<LI><A HREF="#fcompile">Compiling with the forms Library</A> -<LI><A HREF="#foverview">Overview of Forms</A> -<LI><A HREF="#fcreate">Creating and Freeing Fields and Forms</A> -<LI><A HREF="#fattributes">Fetching and Changing Field Attributes</A> -<UL> -<LI><A HREF="#fsizes">Fetching Size and Location Data</A> -<LI><A HREF="#flocation">Changing the Field Location</A> -<LI><A HREF="#fjust">The Justification Attribute</A> -<LI><A HREF="#fdispatts">Field Display Attributes</A> -<LI><A HREF="#foptions">Field Option Bits</A> -<LI><A HREF="#fstatus">Field Status</A> -<LI><A HREF="#fuser">Field User Pointer</A> -</UL> -<LI><A HREF="#fdynamic">Variable-Sized Fields</A> -<LI><A HREF="#fvalidation">Field Validation</A> -<UL> -<LI><A HREF="#ftype_alpha">TYPE_ALPHA</A> -<LI><A HREF="#ftype_alnum">TYPE_ALNUM</A> -<LI><A HREF="#ftype_enum">TYPE_ENUM</A> -<LI><A HREF="#ftype_integer">TYPE_INTEGER</A> -<LI><A HREF="#ftype_numeric">TYPE_NUMERIC</A> -<LI><A HREF="#ftype_regexp">TYPE_REGEXP</A> -</UL> -<LI><A HREF="#fbuffer">Direct Field Buffer Manipulation</A> -<LI><A HREF="#formattrs">Attributes of Forms</A> -<LI><A HREF="#fdisplay">Control of Form Display</A> -<LI><A HREF="#fdriver">Input Processing in the Forms Driver</A> -<UL> -<LI><A HREF="#fpage">Page Navigation Requests</A> -<LI><A HREF="#ffield">Inter-Field Navigation Requests</A> -<LI><A HREF="#fifield">Intra-Field Navigation Requests</A> -<LI><A HREF="#fscroll">Scrolling Requests</A> -<LI><A HREF="#fedit">Field Editing Requests</A> -<LI><A HREF="#forder">Order Requests</A> -<LI><A HREF="#fappcmds">Application Commands</A> -</UL> -<LI><A HREF="#fhooks">Field Change Hooks</A> -<LI><A HREF="#ffocus">Field Change Commands</A> -<LI><A HREF="#frmoptions">Form Options</A> -<LI><A HREF="#fcustom">Custom Validation Types</A> -<UL> -<LI><A HREF="#flinktypes">Union Types</A> -<LI><A HREF="#fnewtypes">New Field Types</A> -<LI><A HREF="#fcheckargs">Validation Function Arguments</A> -<LI><A HREF="#fcustorder">Order Functions For Custom Types</A> -<LI><A HREF="#fcustprobs">Avoiding Problems</A> -</UL> -</UL> -</UL> - -<HR> -<H1><A NAME="introduction">Introduction</A></H1> - -This document is an introduction to programming with <CODE>curses</CODE>. It is -not an exhaustive reference for the curses Application Programming Interface -(API); that role is filled by the <CODE>curses</CODE> manual pages. Rather, it -is intended to help C programmers ease into using the package. <P> - -This document is aimed at C applications programmers not yet specifically -familiar with ncurses. If you are already an experienced <CODE>curses</CODE> -programmer, you should nevertheless read the sections on -<A HREF="#mouse">Mouse Interfacing</A>, <A HREF="#debugging">Debugging</A>, -<A HREF="#compat">Compatibility with Older Versions</A>, -and <A HREF="#hints">Hints, Tips, and Tricks</A>. These will bring you up -to speed on the special features and quirks of the <CODE>ncurses</CODE> -implementation. If you are not so experienced, keep reading. <P> - -The <CODE>curses</CODE> package is a subroutine library for -terminal-independent screen-painting and input-event handling which -presents a high level screen model to the programmer, hiding differences -between terminal types and doing automatic optimization of output to change -one screen full of text into another. <CODE>Curses</CODE> uses terminfo, which -is a database format that can describe the capabilities of thousands of -different terminals. <P> - -The <CODE>curses</CODE> API may seem something of an archaism on UNIX desktops -increasingly dominated by X, Motif, and Tcl/Tk. Nevertheless, UNIX still -supports tty lines and X supports <EM>xterm(1)</EM>; the <CODE>curses</CODE> -API has the advantage of (a) back-portability to character-cell terminals, -and (b) simplicity. For an application that does not require bit-mapped -graphics and multiple fonts, an interface implementation using <CODE>curses</CODE> -will typically be a great deal simpler and less expensive than one using an -X toolkit. <P> - -<H2><A NAME="history">A Brief History of Curses</A></H2> - -Historically, the first ancestor of <CODE>curses</CODE> was the routines written to -provide screen-handling for the game <CODE>rogue</CODE>; these used the -already-existing <CODE>termcap</CODE> database facility for describing terminal -capabilities. These routines were abstracted into a documented library and -first released with the early BSD UNIX versions. <P> - -System III UNIX from Bell Labs featured a rewritten and much-improved -<CODE>curses</CODE> library. It introduced the terminfo format. Terminfo is based -on Berkeley's termcap database, but contains a number of improvements and -extensions. Parameterized capabilities strings were introduced, making it -possible to describe multiple video attributes, and colors and to handle far -more unusual terminals than possible with termcap. In the later AT&T -System V releases, <CODE>curses</CODE> evolved to use more facilities and offer -more capabilities, going far beyond BSD curses in power and flexibility.<P> - -<H2><A NAME="scope">Scope of This Document</A></H2> - -This document describes <CODE>ncurses</CODE>, a free implementation of -the System V <CODE>curses</CODE> API with some clearly marked extensions. -It includes the following System V curses features: <P> -<UL> -<LI>Support for multiple screen highlights (BSD curses could only -handle one `standout' highlight, usually reverse-video). <P> -<LI>Support for line- and box-drawing using forms characters. <P> -<LI>Recognition of function keys on input. <P> -<LI>Color support. <P> -<LI>Support for pads (windows of larger than screen size on which the -screen or a subwindow defines a viewport). -</UL> - -Also, this package makes use of the insert and delete line and character -features of terminals so equipped, and determines how to optimally use these -features with no help from the programmer. It allows arbitrary combinations of -video attributes to be displayed, even on terminals that leave ``magic -cookies'' on the screen to mark changes in attributes. <P> - -The <CODE>ncurses</CODE> package can also capture and use event reports from a -mouse in some environments (notably, xterm under the X window system). This -document includes tips for using the mouse. <P> - -The <CODE>ncurses</CODE> package was originated by Pavel Curtis. The original -maintainer of this package is -<A HREF="mailto:zmbenhal@netcom.com">Zeyd Ben-Halim</A> -<zmbenhal@netcom.com>. -<A HREF="mailto:esr@snark.thyrsus.com">Eric S. Raymond</A> -<esr@snark.thyrsus.com> -wrote many of the new features in versions after 1.8.1 -and wrote most of this introduction. -<A HREF="mailto:juergen.pfeifer@gmx.net">Jürgen Pfeifer</A> -wrote all of the menu and forms code as well as the -<A HREF="http://www.adahome.com">Ada95</A> binding. -Ongoing work is being done by -<A HREF="mailto:dickey@clark.net">Thomas Dickey</A> -and -<A HREF="mailto:juergen.pfeifer@gmx.net">Jürgen Pfeifer</A>. -<A HREF="mailto:florian@gnu.org">Florian La Roche</A> -acts as the maintainer for the Free Software Foundation, which holds the -copyright on ncurses. -Contact the current maintainers at -<A HREF="mailto:bug-ncurses@gnu.org">bug-ncurses@gnu.org</A>. -<P> - -This document also describes the <A HREF="#panels">panels</A> extension library, -similarly modeled on the SVr4 panels facility. This library allows you to -associate backing store with each of a stack or deck of overlapping windows, -and provides operations for moving windows around in the stack that change -their visibility in the natural way (handling window overlaps). <P> - -Finally, this document describes in detail the <A HREF="#menu">menus</A> and <A -HREF="#form">forms</A> extension libraries, also cloned from System V, -which support easy construction and sequences of menus and fill-in -forms. <P> - - -<H2><A NAME="terminology">Terminology</A></H2> - -In this document, the following terminology is used with reasonable -consistency: - -<DL> -<DT> window -<DD> -A data structure describing a sub-rectangle of the screen (possibly the -entire screen). You can write to a window as though it were a miniature -screen, scrolling independently of other windows on the physical screen. <P> -<DT> screens -<DD> -A subset of windows which are as large as the terminal screen, i.e., they start -at the upper left hand corner and encompass the lower right hand corner. One -of these, <CODE>stdscr</CODE>, is automatically provided for the programmer. <P> -<DT> terminal screen -<DD> -The package's idea of what the terminal display currently looks like, i.e., -what the user sees now. This is a special screen. -</DL> - -<H1><A NAME="curses">The Curses Library</A></H1> - -<H2><A NAME="overview">An Overview of Curses</A></H2> - -<H3><A NAME="compiling">Compiling Programs using Curses</A></H3> - -In order to use the library, it is necessary to have certain types and -variables defined. Therefore, the programmer must have a line: - -<PRE> - #include <curses.h> -</PRE> - -at the top of the program source. The screen package uses the Standard I/O -library, so <CODE><curses.h></CODE> includes -<CODE><stdio.h></CODE>. <CODE><curses.h></CODE> also includes -<CODE><termios.h></CODE>, <CODE><termio.h></CODE>, or -<CODE><sgtty.h></CODE> depending on your system. It is redundant (but -harmless) for the programmer to do these includes, too. In linking with -<CODE>curses</CODE> you need to have <CODE>-lncurses</CODE> in your LDFLAGS or on the -command line. There is no need for any other libraries. - -<H3><A NAME="updating">Updating the Screen</A></H3> - -In order to update the screen optimally, it is necessary for the routines to -know what the screen currently looks like and what the programmer wants it to -look like next. For this purpose, a data type (structure) named WINDOW is -defined which describes a window image to the routines, including its starting -position on the screen (the (y, x) coordinates of the upper left hand corner) -and its size. One of these (called <CODE>curscr</CODE>, for current screen) is a -screen image of what the terminal currently looks like. Another screen (called -<CODE>stdscr</CODE>, for standard screen) is provided by default to make changes -on. <P> - -A window is a purely internal representation. It is used to build and store a -potential image of a portion of the terminal. It doesn't bear any necessary -relation to what is really on the terminal screen; it's more like a -scratchpad or write buffer. <P> - -To make the section of physical screen corresponding to a window reflect the -contents of the window structure, the routine <CODE>refresh()</CODE> (or -<CODE>wrefresh()</CODE> if the window is not <CODE>stdscr</CODE>) is called. <P> - -A given physical screen section may be within the scope of any number of -overlapping windows. Also, changes can be made to windows in any order, -without regard to motion efficiency. Then, at will, the programmer can -effectively say ``make it look like this,'' and let the package implementation -determine the most efficient way to repaint the screen. <P> - -<H3><A NAME="stdscr">Standard Windows and Function Naming Conventions</A></H3> - -As hinted above, the routines can use several windows, but two are -automatically given: <CODE>curscr</CODE>, which knows what the terminal looks like, -and <CODE>stdscr</CODE>, which is what the programmer wants the terminal to look -like next. The user should never actually access <CODE>curscr</CODE> directly. -Changes should be made to through the API, and then the routine -<CODE>refresh()</CODE> (or <CODE>wrefresh()</CODE>) called. <P> - -Many functions are defined to use <CODE>stdscr</CODE> as a default screen. For -example, to add a character to <CODE>stdscr</CODE>, one calls <CODE>addch()</CODE> with -the desired character as argument. To write to a different window. use the -routine <CODE>waddch()</CODE> (for `w'indow-specific addch()) is provided. This -convention of prepending function names with a `w' when they are to be -applied to specific windows is consistent. The only routines which do not -follow it are those for which a window must always be specified. <P> - -In order to move the current (y, x) coordinates from one point to another, the -routines <CODE>move()</CODE> and <CODE>wmove()</CODE> are provided. However, it is -often desirable to first move and then perform some I/O operation. In order to -avoid clumsiness, most I/O routines can be preceded by the prefix 'mv' and -the desired (y, x) coordinates prepended to the arguments to the function. For -example, the calls - -<PRE> - move(y, x); - addch(ch); -</PRE> - -can be replaced by - -<PRE> - mvaddch(y, x, ch); -</PRE> - -and - -<PRE> - wmove(win, y, x); - waddch(win, ch); -</PRE> - -can be replaced by - -<PRE> - mvwaddch(win, y, x, ch); -</PRE> - -Note that the window description pointer (win) comes before the added (y, x) -coordinates. If a function requires a window pointer, it is always the first -parameter passed. <P> - -<H3><A NAME="variables">Variables</A></H3> - -The <CODE>curses</CODE> library sets some variables describing the terminal -capabilities. - -<PRE> - type name description - ------------------------------------------------------------------ - int LINES number of lines on the terminal - int COLS number of columns on the terminal -</PRE> - -The <CODE>curses.h</CODE> also introduces some <CODE>#define</CODE> constants and types -of general usefulness: - -<DL> -<DT> <CODE>bool</CODE> -<DD> boolean type, actually a `char' (e.g., <CODE>bool doneit;</CODE>) -<DT> <CODE>TRUE</CODE> -<DD> boolean `true' flag (1). -<DT> <CODE>FALSE</CODE> -<DD> boolean `false' flag (0). -<DT> <CODE>ERR</CODE> -<DD> error flag returned by routines on a failure (-1). -<DT> <CODE>OK</CODE> -<DD> error flag returned by routines when things go right. -</DL> - -<H2><A NAME="using">Using the Library</A></H2> - -Now we describe how to actually use the screen package. In it, we assume all -updating, reading, etc. is applied to <CODE>stdscr</CODE>. These instructions will -work on any window, providing you change the function names and parameters as -mentioned above. <P> - -Here is a sample program to motivate the discussion: <P> - -<PRE> -#include <curses.h> -#include <signal.h> - -static void finish(int sig); - -main(int argc, char *argv[]) -{ - /* initialize your non-curses data structures here */ - - (void) signal(SIGINT, finish); /* arrange interrupts to terminate */ - - (void) initscr(); /* initialize the curses library */ - keypad(stdscr, TRUE); /* enable keyboard mapping */ - (void) nonl(); /* tell curses not to do NL->CR/NL on output */ - (void) cbreak(); /* take input chars one at a time, no wait for \n */ - (void) noecho(); /* don't echo input */ - - if (has_colors()) - { - start_color(); - - /* - * Simple color assignment, often all we need. - */ - init_pair(COLOR_BLACK, COLOR_BLACK, COLOR_BLACK); - init_pair(COLOR_GREEN, COLOR_GREEN, COLOR_BLACK); - init_pair(COLOR_RED, COLOR_RED, COLOR_BLACK); - init_pair(COLOR_CYAN, COLOR_CYAN, COLOR_BLACK); - init_pair(COLOR_WHITE, COLOR_WHITE, COLOR_BLACK); - init_pair(COLOR_MAGENTA, COLOR_MAGENTA, COLOR_BLACK); - init_pair(COLOR_BLUE, COLOR_BLUE, COLOR_BLACK); - init_pair(COLOR_YELLOW, COLOR_YELLOW, COLOR_BLACK); - } - - for (;;) - { - int c = getch(); /* refresh, accept single keystroke of input */ - - /* process the command keystroke */ - } - - finish(0); /* we're done */ -} - -static void finish(int sig) -{ - endwin(); - - /* do your non-curses wrapup here */ - - exit(0); -} -</PRE> - -<H3><A NAME="starting">Starting up</A></H3> - -In order to use the screen package, the routines must know about terminal -characteristics, and the space for <CODE>curscr</CODE> and <CODE>stdscr</CODE> must be -allocated. These function <CODE>initscr()</CODE> does both these things. Since it -must allocate space for the windows, it can overflow memory when attempting to -do so. On the rare occasions this happens, <CODE>initscr()</CODE> will terminate -the program with an error message. <CODE>initscr()</CODE> must always be called -before any of the routines which affect windows are used. If it is not, the -program will core dump as soon as either <CODE>curscr</CODE> or <CODE>stdscr</CODE> are -referenced. However, it is usually best to wait to call it until after you are -sure you will need it, like after checking for startup errors. Terminal status -changing routines like <CODE>nl()</CODE> and <CODE>cbreak()</CODE> should be called -after <CODE>initscr()</CODE>. <P> - -Once the screen windows have been allocated, you can set them up for -your program. If you want to, say, allow a screen to scroll, use -<CODE>scrollok()</CODE>. If you want the cursor to be left in place after -the last change, use <CODE>leaveok()</CODE>. If this isn't done, -<CODE>refresh()</CODE> will move the cursor to the window's current (y, x) -coordinates after updating it. <P> - -You can create new windows of your own using the functions <CODE>newwin()</CODE>, -<CODE>derwin()</CODE>, and <CODE>subwin()</CODE>. The routine <CODE>delwin()</CODE> will -allow you to get rid of old windows. All the options described above can be -applied to any window. <P> - -<H3><A NAME="output">Output</A></H3> - -Now that we have set things up, we will want to actually update the terminal. -The basic functions used to change what will go on a window are -<CODE>addch()</CODE> and <CODE>move()</CODE>. <CODE>addch()</CODE> adds a character at the -current (y, x) coordinates. <CODE>move()</CODE> changes the current (y, x) -coordinates to whatever you want them to be. It returns <CODE>ERR</CODE> if you -try to move off the window. As mentioned above, you can combine the two into -<CODE>mvaddch()</CODE> to do both things at once. <P> - -The other output functions, such as <CODE>addstr()</CODE> and <CODE>printw()</CODE>, -all call <CODE>addch()</CODE> to add characters to the window. <P> - -After you have put on the window what you want there, when you want the portion -of the terminal covered by the window to be made to look like it, you must call -<CODE>refresh()</CODE>. In order to optimize finding changes, <CODE>refresh()</CODE> -assumes that any part of the window not changed since the last -<CODE>refresh()</CODE> of that window has not been changed on the terminal, i.e., -that you have not refreshed a portion of the terminal with an overlapping -window. If this is not the case, the routine <CODE>touchwin()</CODE> is provided -to make it look like the entire window has been changed, thus making -<CODE>refresh()</CODE> check the whole subsection of the terminal for changes. <P> - -If you call <CODE>wrefresh()</CODE> with <CODE>curscr</CODE> as its argument, it will -make the screen look like <CODE>curscr</CODE> thinks it looks like. This is useful -for implementing a command which would redraw the screen in case it get messed -up. <P> - -<H3><A NAME="input">Input</A></H3> - -The complementary function to <CODE>addch()</CODE> is <CODE>getch()</CODE> which, if -echo is set, will call <CODE>addch()</CODE> to echo the character. Since the -screen package needs to know what is on the terminal at all times, if -characters are to be echoed, the tty must be in raw or cbreak mode. Since -initially the terminal has echoing enabled and is in ordinary ``cooked'' mode, -one or the other has to changed before calling <CODE>getch()</CODE>; otherwise, -the program's output will be unpredictable. <P> - -When you need to accept line-oriented input in a window, the functions -<CODE>wgetstr()</CODE> and friends are available. There is even a <CODE>wscanw()</CODE> -function that can do <CODE>scanf()</CODE>(3)-style multi-field parsing on window -input. These pseudo-line-oriented functions turn on echoing while they -execute. <P> - -The example code above uses the call <CODE>keypad(stdscr, TRUE)</CODE> to enable -support for function-key mapping. With this feature, the <CODE>getch()</CODE> code -watches the input stream for character sequences that correspond to arrow and -function keys. These sequences are returned as pseudo-character values. The -<CODE>#define</CODE> values returned are listed in the <CODE>curses.h</CODE> The -mapping from sequences to <CODE>#define</CODE> values is determined by -<CODE>key_</CODE> capabilities in the terminal's terminfo entry. <P> - -<H3><A NAME="formschars">Using Forms Characters</A></H3> - -The <CODE>addch()</CODE> function (and some others, including <CODE>box()</CODE> and -<CODE>border()</CODE>) can accept some pseudo-character arguments which are specially -defined by <CODE>ncurses</CODE>. These are <CODE>#define</CODE> values set up in -the <CODE>curses.h</CODE> header; see there for a complete list (look for -the prefix <CODE>ACS_</CODE>). <P> - -The most useful of the ACS defines are the forms-drawing characters. You can -use these to draw boxes and simple graphs on the screen. If the terminal -does not have such characters, <CODE>curses.h</CODE> will map them to a -recognizable (though ugly) set of ASCII defaults. <P> - -<H3><A NAME="attributes">Character Attributes and Color</A></H3> - -The <CODE>ncurses</CODE> package supports screen highlights including standout, -reverse-video, underline, and blink. It also supports color, which is treated -as another kind of highlight. <P> - -Highlights are encoded, internally, as high bits of the pseudo-character type -(<CODE>chtype</CODE>) that <CODE>curses.h</CODE> uses to represent the contents of a -screen cell. See the <CODE>curses.h</CODE> header file for a complete list of -highlight mask values (look for the prefix <CODE>A_</CODE>).<P> - -There are two ways to make highlights. One is to logical-or the value of the -highlights you want into the character argument of an <CODE>addch()</CODE> call, -or any other output call that takes a <CODE>chtype</CODE> argument. <P> - -The other is to set the current-highlight value. This is logical-or'ed with -any highlight you specify the first way. You do this with the functions -<CODE>attron()</CODE>, <CODE>attroff()</CODE>, and <CODE>attrset()</CODE>; see the manual -pages for details. - -Color is a special kind of highlight. The package actually thinks in terms -of color pairs, combinations of foreground and background colors. The sample -code above sets up eight color pairs, all of the guaranteed-available colors -on black. Note that each color pair is, in effect, given the name of its -foreground color. Any other range of eight non-conflicting values could -have been used as the first arguments of the <CODE>init_pair()</CODE> values. <P> - -Once you've done an <CODE>init_pair()</CODE> that creates color-pair N, you can -use <CODE>COLOR_PAIR(N)</CODE> as a highlight that invokes that particular -color combination. Note that <CODE>COLOR_PAIR(N)</CODE>, for constant N, -is itself a compile-time constant and can be used in initializers. <P> - -<H3><A NAME="mouse">Mouse Interfacing</A></H3> - -The <CODE>ncurses</CODE> library also provides a mouse interface. -<!-- The 'note' tag is not portable enough --> -<blockquote> -<strong>NOTE:</strong> this facility is specific to <CODE>ncurses</CODE>, it is not part of either -the XSI Curses standard, nor of System V Release 4, nor BSD curses. -System V Release 4 curses contains code with similar interface definitions, -however it is not documented. Other than by disassembling the library, we -have no way to determine exactly how that mouse code works. -Thus, we recommend that you wrap mouse-related code in an #ifdef using the -feature macro NCURSES_MOUSE_VERSION so it will not be compiled and linked -on non-ncurses systems. -</blockquote> - -Presently, mouse event reporting works in the following environments: -<ul> -<li>xterm and similar programs such as rxvt. -<li>Linux console, when configured with <CODE>gpm</CODE>(1), Alessandro -Rubini's mouse server. -<li>OS/2 EMX -</ul> -<P> -The mouse interface is very simple. To activate it, you use the function -<CODE>mousemask()</CODE>, passing it as first argument a bit-mask that specifies -what kinds of events you want your program to be able to see. It will -return the bit-mask of events that actually become visible, which may differ -from the argument if the mouse device is not capable of reporting some of -the event types you specify. <P> - -Once the mouse is active, your application's command loop should watch -for a return value of <CODE>KEY_MOUSE</CODE> from <CODE>wgetch()</CODE>. When -you see this, a mouse event report has been queued. To pick it off -the queue, use the function <CODE>getmouse()</CODE> (you must do this before -the next <CODE>wgetch()</CODE>, otherwise another mouse event might come -in and make the first one inaccessible). <P> - -Each call to <CODE>getmouse()</CODE> fills a structure (the address of which you'll -pass it) with mouse event data. The event data includes zero-origin, -screen-relative character-cell coordinates of the mouse pointer. It also -includes an event mask. Bits in this mask will be set, corresponding -to the event type being reported. <P> - -The mouse structure contains two additional fields which may be -significant in the future as ncurses interfaces to new kinds of -pointing device. In addition to x and y coordinates, there is a slot -for a z coordinate; this might be useful with touch-screens that can -return a pressure or duration parameter. There is also a device ID -field, which could be used to distinguish between multiple pointing -devices. <P> - -The class of visible events may be changed at any time via <CODE>mousemask()</CODE>. -Events that can be reported include presses, releases, single-, double- and -triple-clicks (you can set the maximum button-down time for clicks). If -you don't make clicks visible, they will be reported as press-release -pairs. In some environments, the event mask may include bits reporting -the state of shift, alt, and ctrl keys on the keyboard during the event. <P> - -A function to check whether a mouse event fell within a given window is -also supplied. You can use this to see whether a given window should -consider a mouse event relevant to it. <P> - -Because mouse event reporting will not be available in all -environments, it would be unwise to build <CODE>ncurses</CODE> -applications that <EM>require</EM> the use of a mouse. Rather, you should -use the mouse as a shortcut for point-and-shoot commands your application -would normally accept from the keyboard. Two of the test games in the -<CODE>ncurses</CODE> distribution (<CODE>bs</CODE> and <CODE>knight</CODE>) contain -code that illustrates how this can be done. <P> - -See the manual page <CODE>curs_mouse(3X)</CODE> for full details of the -mouse-interface functions. <P> - -<H3><A NAME="finishing">Finishing Up</A></H3> - -In order to clean up after the <CODE>ncurses</CODE> routines, the routine -<CODE>endwin()</CODE> is provided. It restores tty modes to what they were when -<CODE>initscr()</CODE> was first called, and moves the cursor down to the -lower-left corner. Thus, anytime after the call to initscr, <CODE>endwin()</CODE> -should be called before exiting. <P> - -<H2><A NAME="functions">Function Descriptions</A></H2> - -We describe the detailed behavior of some important curses functions here, as a -supplement to the manual page descriptions. - -<H3><A NAME="init">Initialization and Wrapup</A></H3> - -<DL> -<DT> <CODE>initscr()</CODE> -<DD> The first function called should almost always be <CODE>initscr()</CODE>. -This will determine the terminal type and -initialize curses data structures. <CODE>initscr()</CODE> also arranges that -the first call to <CODE>refresh()</CODE> will clear the screen. If an error -occurs a message is written to standard error and the program -exits. Otherwise it returns a pointer to stdscr. A few functions may be -called before initscr (<CODE>slk_init()</CODE>, <CODE>filter()</CODE>, -<CODE>ripofflines()</CODE>, <CODE>use_env()</CODE>, and, if you are using multiple -terminals, <CODE>newterm()</CODE>.) <P> -<DT> <CODE>endwin()</CODE> -<DD> Your program should always call <CODE>endwin()</CODE> before exiting or -shelling out of the program. This function will restore tty modes, -move the cursor to the lower left corner of the screen, reset the -terminal into the proper non-visual mode. Calling <CODE>refresh()</CODE> -or <CODE>doupdate()</CODE> after a temporary escape from the program will -restore the ncurses screen from before the escape. <P> -<DT> <CODE>newterm(type, ofp, ifp)</CODE> -<DD> A program which outputs to more than one terminal should use -<CODE>newterm()</CODE> instead of <CODE>initscr()</CODE>. <CODE>newterm()</CODE> should -be called once for each terminal. It returns a variable of type -<CODE>SCREEN *</CODE> which should be saved as a reference to that -terminal. The arguments are the type of the terminal (a string) and -<CODE>FILE</CODE> pointers for the output and input of the terminal. If -type is NULL then the environment variable <CODE>$TERM</CODE> is used. -<CODE>endwin()</CODE> should called once at wrapup time for each terminal -opened using this function. <P> -<DT> <CODE>set_term(new)</CODE> -<DD> This function is used to switch to a different terminal previously -opened by <CODE>newterm()</CODE>. The screen reference for the new terminal -is passed as the parameter. The previous terminal is returned by the -function. All other calls affect only the current terminal. <P> -<DT> <CODE>delscreen(sp)</CODE> -<DD> The inverse of <CODE>newterm()</CODE>; deallocates the data structures -associated with a given <CODE>SCREEN</CODE> reference. -</DL> - -<H3><A NAME="flush">Causing Output to the Terminal</A></H3> - -<DL> -<DT> <CODE>refresh()</CODE> and <CODE>wrefresh(win)</CODE> -<DD> These functions must be called to actually get any output on -the terminal, as other routines merely manipulate data -structures. <CODE>wrefresh()</CODE> copies the named window to the physical -terminal screen, taking into account what is already -there in order to do optimizations. <CODE>refresh()</CODE> does a -refresh of <CODE>stdscr()</CODE>. Unless <CODE>leaveok()</CODE> has been -enabled, the physical cursor of the terminal is left at the -location of the window's cursor. <P> -<DT> <CODE>doupdate()</CODE> and <CODE>wnoutrefresh(win)</CODE> -<DD> These two functions allow multiple updates with more efficiency -than wrefresh. To use them, it is important to understand how curses -works. In addition to all the window structures, curses keeps two -data structures representing the terminal screen: a physical screen, -describing what is actually on the screen, and a virtual screen, -describing what the programmer wants to have on the screen. wrefresh -works by first copying the named window to the virtual screen -(<CODE>wnoutrefresh()</CODE>), and then calling the routine to update the -screen (<CODE>doupdate()</CODE>). If the programmer wishes to output -several windows at once, a series of calls to <CODE>wrefresh</CODE> will result -in alternating calls to <CODE>wnoutrefresh()</CODE> and <CODE>doupdate()</CODE>, -causing several bursts of output to the screen. By calling -<CODE>wnoutrefresh()</CODE> for each window, it is then possible to call -<CODE>doupdate()</CODE> once, resulting in only one burst of output, with -fewer total characters transmitted (this also avoids a visually annoying -flicker at each update). -</DL> - -<H3><A NAME="lowlevel">Low-Level Capability Access</A></H3> - -<DL> -<DT> <CODE>setupterm(term, filenum, errret)</CODE> -<DD> This routine is called to initialize a terminal's description, without setting -up the curses screen structures or changing the tty-driver mode bits. -<CODE>term</CODE> is the character string representing the name of the terminal -being used. <CODE>filenum</CODE> is the UNIX file descriptor of the terminal to -be used for output. <CODE>errret</CODE> is a pointer to an integer, in which a -success or failure indication is returned. The values returned can be 1 (all -is well), 0 (no such terminal), or -1 (some problem locating the terminfo -database). <P> - -The value of <CODE>term</CODE> can be given as NULL, which will cause the value of -<CODE>TERM</CODE> in the environment to be used. The <CODE>errret</CODE> pointer can -also be given as NULL, meaning no error code is wanted. If <CODE>errret</CODE> is -defaulted, and something goes wrong, <CODE>setupterm()</CODE> will print an -appropriate error message and exit, rather than returning. Thus, a simple -program can call setupterm(0, 1, 0) and not worry about initialization -errors. <P> - -After the call to <CODE>setupterm()</CODE>, the global variable <CODE>cur_term</CODE> is -set to point to the current structure of terminal capabilities. By calling -<CODE>setupterm()</CODE> for each terminal, and saving and restoring -<CODE>cur_term</CODE>, it is possible for a program to use two or more terminals at -once. <CODE>Setupterm()</CODE> also stores the names section of the terminal -description in the global character array <CODE>ttytype[]</CODE>. Subsequent calls -to <CODE>setupterm()</CODE> will overwrite this array, so you'll have to save it -yourself if need be. -</DL> - -<H3><A NAME="debugging">Debugging</A></H3> - -<!-- The 'note' tag is not portable enough --> -<blockquote> -<strong>NOTE:</strong> These functions are not part of the standard curses API! -</blockquote> - -<DL> -<DT> <CODE>trace()</CODE> -<DD> -This function can be used to explicitly set a trace level. If the -trace level is nonzero, execution of your program will generate a file -called `trace' in the current working directory containing a report on -the library's actions. Higher trace levels enable more detailed (and -verbose) reporting -- see comments attached to <CODE>TRACE_</CODE> defines -in the <CODE>curses.h</CODE> file for details. (It is also possible to set -a trace level by assigning a trace level value to the environment variable -<CODE>NCURSES_TRACE</CODE>). -<DT> <CODE>_tracef()</CODE> -<DD> -This function can be used to output your own debugging information. It is only -available only if you link with -lncurses_g. It can be used the same way as -<CODE>printf()</CODE>, only it outputs a newline after the end of arguments. -The output goes to a file called <CODE>trace</CODE> in the current directory. -</DL> - -Trace logs can be difficult to interpret due to the sheer volume of -data dumped in them. There is a script called <STRONG>tracemunch</STRONG> -included with the <CODE>ncurses</CODE> distribution that can alleviate -this problem somewhat; it compacts long sequences of similar operations into -more succinct single-line pseudo-operations. These pseudo-ops can be -distinguished by the fact that they are named in capital letters.<P> - -<H2><A NAME="hints">Hints, Tips, and Tricks</A></H2> - -The <CODE>ncurses</CODE> manual pages are a complete reference for this library. -In the remainder of this document, we discuss various useful methods that -may not be obvious from the manual page descriptions. <P> - -<H3><A NAME="caution">Some Notes of Caution</A></H3> - -If you find yourself thinking you need to use <CODE>noraw()</CODE> or -<CODE>nocbreak()</CODE>, think again and move carefully. It's probably -better design to use <CODE>getstr()</CODE> or one of its relatives to -simulate cooked mode. The <CODE>noraw()</CODE> and <CODE>nocbreak()</CODE> -functions try to restore cooked mode, but they may end up clobbering -some control bits set before you started your application. Also, they -have always been poorly documented, and are likely to hurt your -application's usability with other curses libraries. <P> - -Bear in mind that <CODE>refresh()</CODE> is a synonym for <CODE>wrefresh(stdscr)</CODE>. -Don't try to mix use of <CODE>stdscr</CODE> with use of windows declared -by <CODE>newwin()</CODE>; a <CODE>refresh()</CODE> call will blow them off the -screen. The right way to handle this is to use <CODE>subwin()</CODE>, or -not touch <CODE>stdscr</CODE> at all and tile your screen with declared -windows which you then <CODE>wnoutrefresh()</CODE> somewhere in your program -event loop, with a single <CODE>doupdate()</CODE> call to trigger actual -repainting. <P> - -You are much less likely to run into problems if you design your screen -layouts to use tiled rather than overlapping windows. Historically, -curses support for overlapping windows has been weak, fragile, and poorly -documented. The <CODE>ncurses</CODE> library is not yet an exception to this -rule. <P> - -There is a panels library included in the <CODE>ncurses</CODE> -distribution that does a pretty good job of strengthening the -overlapping-windows facilities. <P> - -Try to avoid using the global variables LINES and COLS. Use -<CODE>getmaxyx()</CODE> on the <CODE>stdscr</CODE> context instead. Reason: -your code may be ported to run in an environment with window resizes, -in which case several screens could be open with different sizes. <P> - -<H3><A NAME="leaving">Temporarily Leaving NCURSES Mode</A></H3> - -Sometimes you will want to write a program that spends most of its time in -screen mode, but occasionally returns to ordinary `cooked' mode. A common -reason for this is to support shell-out. This behavior is simple to arrange -in <CODE>ncurses</CODE>. <P> - -To leave <CODE>ncurses</CODE> mode, call <CODE>endwin()</CODE> as you would if you -were intending to terminate the program. This will take the screen back to -cooked mode; you can do your shell-out. When you want to return to -<CODE>ncurses</CODE> mode, simply call <CODE>refresh()</CODE> or <CODE>doupdate()</CODE>. -This will repaint the screen. <P> - -There is a boolean function, <CODE>isendwin()</CODE>, which code can use to -test whether <CODE>ncurses</CODE> screen mode is active. It returns <CODE>TRUE</CODE> -in the interval between an <CODE>endwin()</CODE> call and the following -<CODE>refresh()</CODE>, <CODE>FALSE</CODE> otherwise. <P> - -Here is some sample code for shellout: - -<PRE> - addstr("Shelling out..."); - def_prog_mode(); /* save current tty modes */ - endwin(); /* restore original tty modes */ - system("sh"); /* run shell */ - addstr("returned.\n"); /* prepare return message */ - refresh(); /* restore save modes, repaint screen */ -</PRE> - -<H3><A NAME="xterm">Using NCURSES under XTERM</A></H3> - -A resize operation in X sends SIGWINCH to the application running under xterm. -The <CODE>ncurses</CODE> library provides an experimental signal -handler, but in general does not catch this signal, because it cannot -know how you want the screen re-painted. You will usually have to write the -SIGWINCH handler yourself. Ncurses can give you some help. <P> - -The easiest way to code your SIGWINCH handler is to have it do an -<CODE>endwin</CODE>, followed by an <CODE>refresh</CODE> and a screen repaint you code -yourself. The <CODE>refresh</CODE> will pick up the new screen size from the -xterm's environment. <P> - -That is the standard way, of course (it even works with some vendor's curses -implementations). -Its drawback is that it clears the screen to reinitialize the display, and does -not resize subwindows which must be shrunk. -<CODE>Ncurses</CODE> provides an extension which works better, the -<CODE>resizeterm</CODE> function. That function ensures that all windows -are limited to the new screen dimensions, and pads <CODE>stdscr</CODE> -with blanks if the screen is larger. <P> - -Finally, ncurses can be configured to provide its own SIGWINCH handler, -based on <CODE>resizeterm</CODE>. - -<H3><A NAME="screens">Handling Multiple Terminal Screens</A></H3> - -The <CODE>initscr()</CODE> function actually calls a function named -<CODE>newterm()</CODE> to do most of its work. If you are writing a program that -opens multiple terminals, use <CODE>newterm()</CODE> directly. <P> - -For each call, you will have to specify a terminal type and a pair of file -pointers; each call will return a screen reference, and <CODE>stdscr</CODE> will be -set to the last one allocated. You will switch between screens with the -<CODE>set_term</CODE> call. Note that you will also have to call -<CODE>def_shell_mode</CODE> and <CODE>def_prog_mode</CODE> on each tty yourself. <P> - -<H3><A NAME="testing">Testing for Terminal Capabilities</A></H3> - -Sometimes you may want to write programs that test for the presence of various -capabilities before deciding whether to go into <CODE>ncurses</CODE> mode. An easy -way to do this is to call <CODE>setupterm()</CODE>, then use the functions -<CODE>tigetflag()</CODE>, <CODE>tigetnum()</CODE>, and <CODE>tigetstr()</CODE> to do your -testing. <P> - -A particularly useful case of this often comes up when you want to -test whether a given terminal type should be treated as `smart' -(cursor-addressable) or `stupid'. The right way to test this is to see -if the return value of <CODE>tigetstr("cup")</CODE> is non-NULL. Alternatively, -you can include the <CODE>term.h</CODE> file and test the value of the -macro <CODE>cursor_address</CODE>. <P> - -<H3><A NAME="tuning">Tuning for Speed</A></H3> - -Use the <CODE>addchstr()</CODE> family of functions for fast -screen-painting of text when you know the text doesn't contain any -control characters. Try to make attribute changes infrequent on your -screens. Don't use the <CODE>immedok()</CODE> option! <P> - -<H3><A NAME="special">Special Features of NCURSES</A></H3> - -The <CODE>wresize()</CODE> function allows you to resize a window in place. -The associated <CODE>resizeterm()</CODE> function simplifies the construction -of <a HREF="#xterm">SIGWINCH</a> handlers, for resizing all windows. <P> - -The <CODE>define_key()</CODE> function allows you -to define at runtime function-key control sequences which are not in the -terminal description. -The <CODE>keyok()</CODE> function allows you to temporarily -enable or disable interpretation of any function-key control sequence. <P> - -The <CODE>use_default_colors()</CODE> function allows you to construct -applications which can use the terminal's default foreground and -background colors as an additional "default" color. -Several terminal emulators support this feature, which is based on ISO 6429. <P> - -Ncurses supports up 16 colors, unlike SVr4 curses which defines only 8. -While most terminals which provide color allow only 8 colors, about -a quarter (including XFree86 xterm) support 16 colors. - -<H2><A NAME="compat">Compatibility with Older Versions</A></H2> - -Despite our best efforts, there are some differences between <CODE>ncurses</CODE> -and the (undocumented!) behavior of older curses implementations. These arise -from ambiguities or omissions in the documentation of the API. - -<H3><A NAME="refbug">Refresh of Overlapping Windows</A></H3> - -If you define two windows A and B that overlap, and then alternately scribble -on and refresh them, the changes made to the overlapping region under historic -<CODE>curses</CODE> versions were often not documented precisely. <P> - -To understand why this is a problem, remember that screen updates are -calculated between two representations of the <EM>entire</EM> display. The -documentation says that when you refresh a window, it is first copied to to the -virtual screen, and then changes are calculated to update the physical screen -(and applied to the terminal). But "copied to" is not very specific, and -subtle differences in how copying works can produce different behaviors in the -case where two overlapping windows are each being refreshed at unpredictable -intervals. <P> - -What happens to the overlapping region depends on what <CODE>wnoutrefresh()</CODE> -does with its argument -- what portions of the argument window it copies to the -virtual screen. Some implementations do "change copy", copying down only -locations in the window that have changed (or been marked changed with -<CODE>wtouchln()</CODE> and friends). Some implementations do "entire copy", -copying <EM>all</EM> window locations to the virtual screen whether or not -they have changed. <P> - -The <CODE>ncurses</CODE> library itself has not always been consistent on this -score. Due to a bug, versions 1.8.7 to 1.9.8a did entire copy. Versions -1.8.6 and older, and versions 1.9.9 and newer, do change copy. <P> - -For most commercial curses implementations, it is not documented and not known -for sure (at least not to the <CODE>ncurses</CODE> maintainers) whether they do -change copy or entire copy. We know that System V release 3 curses has logic -in it that looks like an attempt to do change copy, but the surrounding logic -and data representations are sufficiently complex, and our knowledge -sufficiently indirect, that it's hard to know whether this is reliable. - -It is not clear what the SVr4 documentation and XSI standard intend. The XSI -Curses standard barely mentions wnoutrefresh(); the SVr4 documents seem to be -describing entire-copy, but it is possible with some effort and straining to -read them the other way. <P> - -It might therefore be unwise to rely on either behavior in programs that might -have to be linked with other curses implementations. Instead, you can do an -explicit <CODE>touchwin()</CODE> before the <CODE>wnoutrefresh()</CODE> call to -guarantee an entire-contents copy anywhere. <P> - -The really clean way to handle this is to use the panels library. If, -when you want a screen update, you do <CODE>update_panels()</CODE>, it will -do all the necessary <CODE>wnoutrfresh()</CODE> calls for whatever panel -stacking order you have defined. Then you can do one <CODE>doupdate()</CODE> -and there will be a <EM>single</EM> burst of physical I/O that will do -all your updates. <P> - -<H3><A NAME="backbug">Background Erase</A></H3> - -If you have been using a very old versions of <CODE>ncurses</CODE> (1.8.7 or -older) you may be surprised by the behavior of the erase functions. In older -versions, erased areas of a window were filled with a blank modified by the -window's current attribute (as set by <STRONG>wattrset()</STRONG>, <STRONG>wattron()</STRONG>, -<STRONG>wattroff()</STRONG> and friends). <P> - -In newer versions, this is not so. Instead, the attribute of erased blanks -is normal unless and until it is modified by the functions <CODE>bkgdset()</CODE> -or <CODE>wbkgdset()</CODE>. <P> - -This change in behavior conforms <CODE>ncurses</CODE> to System V Release 4 and -the XSI Curses standard. <P> - -<H2><A NAME="xsifuncs">XSI Curses Conformance</A></H2> - -The <CODE>ncurses</CODE> library is intended to be base-level conformant with the -XSI Curses standard from X/Open. Many extended-level features (in fact, almost -all features not directly concerned with wide characters and -internationalization) are also supported. <P> - -One effect of XSI conformance is the change in behavior described under -<A HREF="#backbug">"Background Erase -- Compatibility with Old Versions"</A>. <P> - -Also, <CODE>ncurses</CODE> meets the XSI requirement that every macro -entry point have a corresponding function which may be linked (and -will be prototype-checked) if the macro definition is disabled with -<CODE>#undef</CODE>. <P> - -<H1><A NAME="panels">The Panels Library</A></H1> - -The <CODE>ncurses</CODE> library by itself provides good support for screen -displays in which the windows are tiled (non-overlapping). In the more -general case that windows may overlap, you have to use a series of -<CODE>wnoutrefresh()</CODE> calls followed by a <CODE>doupdate()</CODE>, and be -careful about the order you do the window refreshes in. It has to be -bottom-upwards, otherwise parts of windows that should be obscured will -show through. <P> - -When your interface design is such that windows may dive deeper into the -visibility stack or pop to the top at runtime, the resulting book-keeping -can be tedious and difficult to get right. Hence the panels library. <P> - -The <CODE>panel</CODE> library first appeared in AT&T System V. The -version documented here is the <CODE>panel</CODE> code distributed -with <CODE>ncurses</CODE>. - -<H2><A NAME="pcompile">Compiling With the Panels Library</A></H2> - -Your panels-using modules must import the panels library declarations with - -<PRE> - #include <panel.h> -</PRE> - -and must be linked explicitly with the panels library using an -<CODE>-lpanel</CODE> argument. Note that they must also link the -<CODE>ncurses</CODE> library with <CODE>-lncurses</CODE>. Many linkers -are two-pass and will accept either order, but it is still good practice -to put <CODE>-lpanel</CODE> first and <CODE>-lncurses</CODE> second. - -<H2><A NAME="poverview">Overview of Panels</A></H2> - -A panel object is a window that is implicitly treated as part of a -<DFN>deck</DFN> including all other panel objects. The deck has an implicit -bottom-to-top visibility order. The panels library includes an update -function (analogous to <CODE>refresh()</CODE>) that displays all panels in the -deck in the proper order to resolve overlaps. The standard window, -<CODE>stdscr</CODE>, is considered below all panels. <P> - -Details on the panels functions are available in the man pages. We'll just -hit the highlights here. <P> - -You create a panel from a window by calling <CODE>new_panel()</CODE> on a -window pointer. It then becomes the top of the deck. The panel's window -is available as the value of <CODE>panel_window()</CODE> called with the -panel pointer as argument.<P> - -You can delete a panel (removing it from the deck) with <CODE>del_panel</CODE>. -This will not deallocate the associated window; you have to do that yourself. - -You can replace a panel's window with a different window by calling -<CODE>replace_window</CODE>. The new window may be of different size; -the panel code will re-compute all overlaps. This operation doesn't -change the panel's position in the deck. <P> - -To move a panel's window, use <CODE>move_panel()</CODE>. The -<CODE>mvwin()</CODE> function on the panel's window isn't sufficient because it -doesn't update the panels library's representation of where the windows are. -This operation leaves the panel's depth, contents, and size unchanged. <P> - -Two functions (<CODE>top_panel()</CODE>, <CODE>bottom_panel()</CODE>) are -provided for rearranging the deck. The first pops its argument window to the -top of the deck; the second sends it to the bottom. Either operation leaves -the panel's screen location, contents, and size unchanged. <P> - -The function <CODE>update_panels()</CODE> does all the -<CODE>wnoutrefresh()</CODE> calls needed to prepare for -<CODE>doupdate()</CODE> (which you must call yourself, afterwards). <P> - -Typically, you will want to call <CODE>update_panels()</CODE> and -<CODE>doupdate()</CODE> just before accepting command input, once in each cycle -of interaction with the user. If you call <CODE>update_panels()</CODE> after -each and every panel write, you'll generate a lot of unnecessary refresh -activity and screen flicker. <P> - -<H2><A NAME="pstdscr">Panels, Input, and the Standard Screen</A></H2> - -You shouldn't mix <CODE>wnoutrefresh()</CODE> or <CODE>wrefresh()</CODE> -operations with panels code; this will work only if the argument window -is either in the top panel or unobscured by any other panels. <P> - -The <CODE>stsdcr</CODE> window is a special case. It is considered below all -panels. Because changes to panels may obscure parts of <CODE>stdscr</CODE>, -though, you should call <CODE>update_panels()</CODE> before -<CODE>doupdate()</CODE> even when you only change <CODE>stdscr</CODE>. <P> - -Note that <CODE>wgetch</CODE> automatically calls <CODE>wrefresh</CODE>. -Therefore, before requesting input from a panel window, you need to be sure -that the panel is totally unobscured. <P> - -There is presently no way to display changes to one obscured panel without -repainting all panels. <P> - -<H2><A NAME="hiding">Hiding Panels</A></H2> - -It's possible to remove a panel from the deck temporarily; use -<CODE>hide_panel</CODE> for this. Use <CODE>show_panel()</CODE> to render it -visible again. The predicate function <CODE>panel_hidden</CODE> -tests whether or not a panel is hidden. <P> - -The <CODE>panel_update</CODE> code ignores hidden panels. You cannot do -<CODE>top_panel()</CODE> or <CODE>bottom_panel</CODE> on a hidden panel(). -Other panels operations are applicable. <P> - -<H2><A NAME="pmisc">Miscellaneous Other Facilities</A></H2> - -It's possible to navigate the deck using the functions -<CODE>panel_above()</CODE> and <CODE>panel_below</CODE>. Handed a panel -pointer, they return the panel above or below that panel. Handed -<CODE>NULL</CODE>, they return the bottom-most or top-most panel. <P> - -Every panel has an associated user pointer, not used by the panel code, to -which you can attach application data. See the man page documentation -of <CODE>set_panel_userptr()</CODE> and <CODE>panel_userptr</CODE> for -details. <P> - -<H1><A NAME="menu">The Menu Library</A></H1> - -A menu is a screen display that assists the user to choose some subset -of a given set of items. The <CODE>menu</CODE> library is a curses -extension that supports easy programming of menu hierarchies with a -uniform but flexible interface. <P> - -The <CODE>menu</CODE> library first appeared in AT&T System V. The -version documented here is the <CODE>menu</CODE> code distributed -with <CODE>ncurses</CODE>. <P> - -<H2><A NAME="mcompile">Compiling With the menu Library</A></H2> - -Your menu-using modules must import the menu library declarations with - -<PRE> - #include <menu.h> -</PRE> - -and must be linked explicitly with the menus library using an -<CODE>-lmenu</CODE> argument. Note that they must also link the -<CODE>ncurses</CODE> library with <CODE>-lncurses</CODE>. Many linkers -are two-pass and will accept either order, but it is still good practice -to put <CODE>-lmenu</CODE> first and <CODE>-lncurses</CODE> second. - -<H2><A NAME="moverview">Overview of Menus</A></H2> - -The menus created by this library consist of collections of -<DFN>items</DFN> including a name string part and a description string -part. To make menus, you create groups of these items and connect -them with menu frame objects. <P> - -The menu can then by <DFN>posted</DFN>, that is written to an -associated window. Actually, each menu has two associated windows; a -containing window in which the programmer can scribble titles or -borders, and a subwindow in which the menu items proper are displayed. -If this subwindow is too small to display all the items, it will be a -scrollable viewport on the collection of items. <P> - -A menu may also be <DFN>unposted</DFN> (that is, undisplayed), and finally -freed to make the storage associated with it and its items available for -re-use. <P> - -The general flow of control of a menu program looks like this: - -<OL> -<LI>Initialize <CODE>curses</CODE>. -<LI>Create the menu items, using <CODE>new_item()</CODE>. -<LI>Create the menu using <CODE>new_menu()</CODE>. -<LI>Post the menu using <CODE>menu_post()</CODE>. -<LI>Refresh the screen. -<LI>Process user requests via an input loop. -<LI>Unpost the menu using <CODE>menu_unpost()</CODE>. -<LI>Free the menu, using <CODE>free_menu()</CODE>. -<LI>Free the items using <CODE>free_item()</CODE>. -<LI>Terminate <CODE>curses</CODE>. -</OL> - -<H2><A NAME="mselect">Selecting items</A></H2> - -Menus may be multi-valued or (the default) single-valued (see the manual -page <CODE>menu_opts(3x)</CODE> to see how to change the default). -Both types always have a <DFN>current item</DFN>. <P> - -From a single-valued menu you can read the selected value simply by looking -at the current item. From a multi-valued menu, you get the selected set -by looping through the items applying the <CODE>item_value()</CODE> -predicate function. Your menu-processing code can use the function -<CODE>set_item_value()</CODE> to flag the items in the select set. <P> - -Menu items can be made unselectable using <CODE>set_item_opts()</CODE> -or <CODE>item_opts_off()</CODE> with the <CODE>O_SELECTABLE</CODE> -argument. This is the only option so far defined for menus, but it -is good practice to code as though other option bits might be on. <P> - -<H2><A NAME="mdisplay">Menu Display</A></H2> - -The menu library calculates a minimum display size for your window, based -on the following variables: <P> - -<UL> -<LI>The number and maximum length of the menu items -<LI>Whether the O_ROWMAJOR option is enabled -<LI>Whether display of descriptions is enabled -<LI>Whatever menu format may have been set by the programmer -<LI>The length of the menu mark string used for highlighting selected items -</UL> - -The function <CODE>set_menu_format()</CODE> allows you to set the -maximum size of the viewport or <DFN>menu page</DFN> that will be used -to display menu items. You can retrieve any format associated with a -menu with <CODE>menu_format()</CODE>. The default format is rows=16, -columns=1. <P> - -The actual menu page may be smaller than the format size. This depends -on the item number and size and whether O_ROWMAJOR is on. This option -(on by default) causes menu items to be displayed in a `raster-scan' -pattern, so that if more than one item will fit horizontally the first -couple of items are side-by-side in the top row. The alternative is -column-major display, which tries to put the first several items in -the first column. <P> - -As mentioned above, a menu format not large enough to allow all items to fit -on-screen will result in a menu display that is vertically scrollable. <P> -You can scroll it with requests to the menu driver, which will be described -in the section on <A HREF="#minput">menu input handling</A>. <P> - -Each menu has a <DFN>mark string</DFN> used to visually tag selected items; -see the <CODE>menu_mark(3x)</CODE> manual page for details. The mark -string length also influences the menu page size. <P> - -The function <CODE>scale_menu()</CODE> returns the minimum display size -that the menu code computes from all these factors. - -There are other menu display attributes including a select attribute, -an attribute for selectable items, an attribute for unselectable items, -and a pad character used to separate item name text from description -text. These have reasonable defaults which the library allows you to -change (see the <CODE>menu_attribs(3x)</CODE> manual page. <P> - -<H2><A NAME="mwindows">Menu Windows</A></H2> - -Each menu has, as mentioned previously, a pair of associated windows. -Both these windows are painted when the menu is posted and erased when -the menu is unposted. <P> - -The outer or frame window is not otherwise touched by the menu -routines. It exists so the programmer can associate a title, a -border, or perhaps help text with the menu and have it properly -refreshed or erased at post/unpost time. The inner window or -<DFN>subwindow</DFN> is where the current menu page is displayed. <P> - -By default, both windows are <CODE>stdscr</CODE>. You can set them with the -functions in <CODE>menu_win(3x)</CODE>. <P> - -When you call <CODE>menu_post()</CODE>, you write the menu to its -subwindow. When you call <CODE>menu_unpost()</CODE>, you erase the -subwindow, However, neither of these actually modifies the screen. To -do that, call <CODE>wrefresh()</CODE> or some equivalent. <P> - -<H2><A NAME="minput">Processing Menu Input</A></H2> - -The main loop of your menu-processing code should call -<CODE>menu_driver()</CODE> repeatedly. The first argument of this routine -is a menu pointer; the second is a menu command code. You should write an -input-fetching routine that maps input characters to menu command codes, and -pass its output to <CODE>menu_driver()</CODE>. The menu command codes are -fully documented in <CODE>menu_driver(3x)</CODE>. <P> - -The simplest group of command codes is <CODE>REQ_NEXT_ITEM</CODE>, -<CODE>REQ_PREV_ITEM</CODE>, <CODE>REQ_FIRST_ITEM</CODE>, -<CODE>REQ_LAST_ITEM</CODE>, <CODE>REQ_UP_ITEM</CODE>, -<CODE>REQ_DOWN_ITEM</CODE>, <CODE>REQ_LEFT_ITEM</CODE>, -<CODE>REQ_RIGHT_ITEM</CODE>. These change the currently selected -item. These requests may cause scrolling of the menu page if it only -partially displayed. <P> - -There are explicit requests for scrolling which also change the -current item (because the select location does not change, but the -item there does). These are <CODE>REQ_SCR_DLINE</CODE>, -<CODE>REQ_SCR_ULINE</CODE>, <CODE>REQ_SCR_DPAGE</CODE>, and -<CODE>REQ_SCR_UPAGE</CODE>. <P> - -The <CODE>REQ_TOGGLE_ITEM</CODE> selects or deselects the current item. -It is for use in multi-valued menus; if you use it with <CODE>O_ONEVALUE</CODE> -on, you'll get an error return (<CODE>E_REQUEST_DENIED</CODE>). <P> - -Each menu has an associated pattern buffer. The -<CODE>menu_driver()</CODE> logic tries to accumulate printable ASCII -characters passed in in that buffer; when it matches a prefix of an -item name, that item (or the next matching item) is selected. If -appending a character yields no new match, that character is deleted -from the pattern buffer, and <CODE>menu_driver()</CODE> returns -<CODE>E_NO_MATCH</CODE>. <P> - -Some requests change the pattern buffer directly: -<CODE>REQ_CLEAR_PATTERN</CODE>, <CODE>REQ_BACK_PATTERN</CODE>, -<CODE>REQ_NEXT_MATCH</CODE>, <CODE>REQ_PREV_MATCH</CODE>. The latter -two are useful when pattern buffer input matches more than one item -in a multi-valued menu. <P> - -Each successful scroll or item navigation request clears the pattern -buffer. It is also possible to set the pattern buffer explicitly -with <CODE>set_menu_pattern()</CODE>. <P> - -Finally, menu driver requests above the constant <CODE>MAX_COMMAND</CODE> -are considered application-specific commands. The <CODE>menu_driver()</CODE> -code ignores them and returns <CODE>E_UNKNOWN_COMMAND</CODE>. - -<H2><A NAME="mmisc">Miscellaneous Other Features</A></H2> - -Various menu options can affect the processing and visual appearance -and input processing of menus. See <CODE>menu_opts(3x) for -details.</CODE> <P> - -It is possible to change the current item from application code; this -is useful if you want to write your own navigation requests. It is -also possible to explicitly set the top row of the menu display. See -<CODE>mitem_current(3x)</CODE>. - -If your application needs to change the menu subwindow cursor for -any reason, <CODE>pos_menu_cursor()</CODE> will restore it to the -correct location for continuing menu driver processing. <P> - -It is possible to set hooks to be called at menu initialization and -wrapup time, and whenever the selected item changes. See -<CODE>menu_hook(3x)</CODE>. <P> - -Each item, and each menu, has an associated user pointer on which you -can hang application data. See <CODE>mitem_userptr(3x)</CODE> and -<CODE>menu_userptr(3x)</CODE>. <P> - -<H1><A NAME="form">The Forms Library</A></H1> - -The <CODE>form</CODE> library is a curses extension that supports easy -programming of on-screen forms for data entry and program control. <P> - -The <CODE>form</CODE> library first appeared in AT&T System V. The -version documented here is the <CODE>form</CODE> code distributed -with <CODE>ncurses</CODE>. <P> - -<H2><A NAME="fcompile">Compiling With the form Library</A></H2> - -Your form-using modules must import the form library declarations with - -<PRE> - #include <form.h> -</PRE> - -and must be linked explicitly with the forms library using an -<CODE>-lform</CODE> argument. Note that they must also link the -<CODE>ncurses</CODE> library with <CODE>-lncurses</CODE>. Many linkers -are two-pass and will accept either order, but it is still good practice -to put <CODE>-lform</CODE> first and <CODE>-lncurses</CODE> second. <P> - -<H2><A NAME="foverview">Overview of Forms</A></H2> - -A form is a collection of fields; each field may be either a label -(explanatory text) or a data-entry location. Long forms may be -segmented into pages; each entry to a new page clears the screen. <P> -To make forms, you create groups of fields and connect them with form -frame objects; the form library makes this relatively simple. <P> - -Once defined, a form can be <DFN>posted</DFN>, that is written to an -associated window. Actually, each form has two associated windows; a -containing window in which the programmer can scribble titles or -borders, and a subwindow in which the form fields proper are displayed. <P> - -As the form user fills out the posted form, navigation and editing -keys support movement between fields, editing keys support modifying -field, and plain text adds to or changes data in a current field. The -form library allows you (the forms designer) to bind each navigation -and editing key to any keystroke accepted by <CODE>curses</CODE> - -Fields may have validation conditions on them, so that they check input -data for type and value. The form library supplies a rich set of -pre-defined field types, and makes it relatively easy to define new ones. <P> - -Once its transaction is completed (or aborted), a form may be -<DFN>unposted</DFN> (that is, undisplayed), and finally freed to make -the storage associated with it and its items available for re-use. <P> - -The general flow of control of a form program looks like this: - -<OL> -<LI>Initialize <CODE>curses</CODE>. -<LI>Create the form fields, using <CODE>new_field()</CODE>. -<LI>Create the form using <CODE>new_form()</CODE>. -<LI>Post the form using <CODE>form_post()</CODE>. -<LI>Refresh the screen. -<LI>Process user requests via an input loop. -<LI>Unpost the form using <CODE>form_unpost()</CODE>. -<LI>Free the form, using <CODE>free_form()</CODE>. -<LI>Free the fields using <CODE>free_field()</CODE>. -<LI>Terminate <CODE>curses</CODE>. -</OL> - -Note that this looks much like a menu program; the form library handles -tasks which are in many ways similar, and its interface was obviously -designed to resemble that of the <A HREF="#menu">menu library</A> -wherever possible. <P> - -In forms programs, however, the `process user requests' is somewhat more -complicated than for menus. Besides menu-like navigation operations, -the menu driver loop has to support field editing and data validation. <P> - -<H2><A NAME="fcreate">Creating and Freeing Fields and Forms</A></H2> - -The basic function for creating fields is <CODE>new_field()</CODE>: <P> - -<PRE> -FIELD *new_field(int height, int width, /* new field size */ - int top, int left, /* upper left corner */ - int offscreen, /* number of offscreen rows */ - int nbuf); /* number of working buffers */ -</PRE> - -Menu items always occupy a single row, but forms fields may have -multiple rows. So <CODE>new_field()</CODE> requires you to specify a -width and height (the first two arguments, which mist both be greater -than zero). <P> - -You must also specify the location of the field's upper left corner on -the screen (the third and fourth arguments, which must be zero or -greater). Note that these coordinates are relative to the form -subwindow, which will coincide with <CODE>stdscr</CODE> by default but -need not be <CODE>stdscr</CODE> if you've done an explicit -<CODE>set_form_window()</CODE> call. <P> - -The fifth argument allows you to specify a number of off-screen rows. If -this is zero, the entire field will always be displayed. If it is -nonzero, the form will be scrollable, with only one screen-full (initially -the top part) displayed at any given time. If you make a field dynamic -and grow it so it will no longer fit on the screen, the form will become -scrollable even if the <CODE>offscreen</CODE> argument was initially zero. <P> - -The forms library allocates one working buffer per field; the size of -each buffer is <CODE>((height + offscreen)*width + 1</CODE>, one character -for each position in the field plus a NUL terminator. The sixth -argument is the number of additional data buffers to allocate for the -field; your application can use them for its own purposes. <P> - -<PRE> -FIELD *dup_field(FIELD *field, /* field to copy */ - int top, int left); /* location of new copy */ -</PRE> - -The function <CODE>dup_field()</CODE> duplicates an existing field at a -new location. Size and buffering information are copied; some -attribute flags and status bits are not (see the -<CODE>form_field_new(3X)</CODE> for details). <P> - -<PRE> -FIELD *link_field(FIELD *field, /* field to copy */ - int top, int left); /* location of new copy */ -</PRE> - -The function <CODE>link_field()</CODE> also duplicates an existing field -at a new location. The difference from <CODE>dup_field()</CODE> is that -it arranges for the new field's buffer to be shared with the old one. <P> - -Besides the obvious use in making a field editable from two different -form pages, linked fields give you a way to hack in dynamic labels. If -you declare several fields linked to an original, and then make them -inactive, changes from the original will still be propagated to the -linked fields. <P> - -As with duplicated fields, linked fields have attribute bits separate -from the original. <P> - -As you might guess, all these field-allocations return <CODE>NULL</CODE> if -the field allocation is not possible due to an out-of-memory error or -out-of-bounds arguments. <P> - -To connect fields to a form, use <P> - -<PRE> -FORM *new_form(FIELD **fields); -</PRE> - -This function expects to see a NULL-terminated array of field pointers. -Said fields are connected to a newly-allocated form object; its address -is returned (or else NULL if the allocation fails). <P> - -Note that <CODE>new_field()</CODE> does <EM>not</EM> copy the pointer array -into private storage; if you modify the contents of the pointer array -during forms processing, all manner of bizarre things might happen. Also -note that any given field may only be connected to one form. <P> - -The functions <CODE>free_field()</CODE> and <CODE>free_form</CODE> are available -to free field and form objects. It is an error to attempt to free a field -connected to a form, but not vice-versa; thus, you will generally free -your form objects first. <P> - -<H2><A NAME="fattributes">Fetching and Changing Field Attributes</A></H2> - -Each form field has a number of location and size attributes -associated with it. There are other field attributes used to control -display and editing of the field. Some (for example, the <CODE>O_STATIC</CODE> bit) -involve sufficient complications to be covered in sections of their own -later on. We cover the functions used to get and set several basic -attributes here. <P> - -When a field is created, the attributes not specified by the -<CODE>new_field</CODE> function are copied from an invisible system -default field. In attribute-setting and -fetching functions, the -argument NULL is taken to mean this field. Changes to it persist -as defaults until your forms application terminates. <P> - -<H3><A NAME="fsizes">Fetching Size and Location Data</A></H3> - -You can retrieve field sizes and locations through: <P> - -<PRE> -int field_info(FIELD *field, /* field from which to fetch */ - int *height, *int width, /* field size */ - int *top, int *left, /* upper left corner */ - int *offscreen, /* number of offscreen rows */ - int *nbuf); /* number of working buffers */ -</PRE> - -This function is a sort of inverse of <CODE>new_field()</CODE>; instead of -setting size and location attributes of a new field, it fetches them -from an existing one. <P> - -<H3><A NAME="flocation">Changing the Field Location</A></H3> - -It is possible to move a field's location on the screen: <P> - -<PRE> -int move_field(FIELD *field, /* field to alter */ - int top, int left); /* new upper-left corner */ -</PRE> - -You can, of course. query the current location through <CODE>field_info()</CODE>. - -<H3><A NAME="fjust">The Justification Attribute</A></H3> - -One-line fields may be unjustified, justified right, justified left, -or centered. Here is how you manipulate this attribute: <P> - -<PRE> -int set_field_just(FIELD *field, /* field to alter */ - int justmode); /* mode to set */ - -int field_just(FIELD *field); /* fetch mode of field */ -</PRE> - -The mode values accepted and returned by this functions are -preprocessor macros <CODE>NO_JUSTIFICATION</CODE>, <CODE>JUSTIFY_RIGHT</CODE>, -<CODE>JUSTIFY_LEFT</CODE>, or <CODE>JUSTIFY_CENTER</CODE>. <P> - -<H3><A NAME="fdispatts">Field Display Attributes</A></H3> - -For each field, you can set a foreground attribute for entered -characters, a background attribute for the entire field, and a pad -character for the unfilled portion of the field. You can also -control pagination of the form. <P> - -This group of four field attributes controls the visual appearance -of the field on the screen, without affecting in any way the data -in the field buffer. <P> - -<PRE> -int set_field_fore(FIELD *field, /* field to alter */ - chtype attr); /* attribute to set */ - -chtype field_fore(FIELD *field); /* field to query */ - -int set_field_back(FIELD *field, /* field to alter */ - chtype attr); /* attribute to set */ - -chtype field_back(FIELD *field); /* field to query */ - -int set_field_pad(FIELD *field, /* field to alter */ - int pad); /* pad character to set */ - -chtype field_pad(FIELD *field); - -int set_new_page(FIELD *field, /* field to alter */ - int flag); /* TRUE to force new page */ - -chtype new_page(FIELD *field); /* field to query */ -</PRE> - -The attributes set and returned by the first four functions are normal -<CODE>curses(3x)</CODE> display attribute values (<CODE>A_STANDOUT</CODE>, -<CODE>A_BOLD</CODE>, <CODE>A_REVERSE</CODE> etc). - -The page bit of a field controls whether it is displayed at the start of -a new form screen. <P> - -<H3><A NAME="foptions">Field Option Bits</A></H3> - -There is also a large collection of field option bits you can set to control -various aspects of forms processing. You can manipulate them with these -functions: - -<PRE> -int set_field_opts(FIELD *field, /* field to alter */ - int attr); /* attribute to set */ - -int field_opts_on(FIELD *field, /* field to alter */ - int attr); /* attributes to turn on */ - -int field_opts_off(FIELD *field, /* field to alter */ - int attr); /* attributes to turn off */ - -int field_opts(FIELD *field); /* field to query */ -</PRE> - -By default, all options are on. Here are the available option bits: -<DL> -<DT> O_VISIBLE -<DD> Controls whether the field is visible on the screen. Can be used -during form processing to hide or pop up fields depending on the value -of parent fields. -<DT> O_ACTIVE -<DD> Controls whether the field is active during forms processing (i.e. -visited by form navigation keys). Can be used to make labels or derived -fields with buffer values alterable by the forms application, not the user. -<DT> O_PUBLIC -<DD> Controls whether data is displayed during field entry. If this option is -turned off on a field, the library will accept and edit data in that field, -but it will not be displayed and the visible field cursor will not move. -You can turn off the O_PUBLIC bit to define password fields. -<DT> O_EDIT -<DD> Controls whether the field's data can be modified. When this option is -off, all editing requests except <CODE>REQ_PREV_CHOICE</CODE> and -<CODE>REQ_NEXT_CHOICE</CODE> will fail. Such read-only fields may be useful for -help messages. -<DT> O_WRAP -<DD> Controls word-wrapping in multi-line fields. Normally, when any -character of a (blank-separated) word reaches the end of the current line, the -entire word is wrapped to the next line (assuming there is one). When this -option is off, the word will be split across the line break. -<DT> O_BLANK -<DD> Controls field blanking. When this option is on, entering a character at -the first field position erases the entire field (except for the just-entered -character). -<DT> O_AUTOSKIP -<DD> Controls automatic skip to next field when this one fills. Normally, -when the forms user tries to type more data into a field than will fit, -the editing location jumps to next field. When this option is off, the -user's cursor will hang at the end of the field. This option is ignored -in dynamic fields that have not reached their size limit. -<DT> O_NULLOK -<DD> Controls whether <A HREF="#fvalidation">validation</A> is applied to -blank fields. Normally, it is not; the user can leave a field blank -without invoking the usual validation check on exit. If this option is -off on a field, exit from it will invoke a validation check. -<DT> O_PASSOK -<DD> Controls whether validation occurs on every exit, or only after -the field is modified. Normally the latter is true. Setting O_PASSOK -may be useful if your field's validation function may change during -forms processing. -<DT> O_STATIC -<DD> Controls whether the field is fixed to its initial dimensions. If you -turn this off, the field becomes <A HREF="#fdynamic">dynamic</A> and will -stretch to fit entered data. -</DL> - -A field's options cannot be changed while the field is currently selected. -However, options may be changed on posted fields that are not current. <P> - -The option values are bit-masks and can be composed with logical-or in -the obvious way. <P> - -<H2><A NAME="fstatus">Field Status</A></H2> - -Every field has a status flag, which is set to FALSE when the field is -created and TRUE when the value in field buffer 0 changes. This flag can -be queried and set directly: <P> - -<PRE> -int set_field_status(FIELD *field, /* field to alter */ - int status); /* mode to set */ - -int field_status(FIELD *field); /* fetch mode of field */ -</PRE> - -Setting this flag under program control can be useful if you use the same -form repeatedly, looking for modified fields each time. <P> - -Calling <CODE>field_status()</CODE> on a field not currently selected -for input will return a correct value. Calling <CODE>field_status()</CODE> on a -field that is currently selected for input may not necessarily give a -correct field status value, because entered data isn't necessarily copied to -buffer zero before the exit validation check. - -To guarantee that the returned status value reflects reality, call -<CODE>field_status()</CODE> either (1) in the field's exit validation check -routine, (2) from the field's or form's initialization or termination -hooks, or (3) just after a <CODE>REQ_VALIDATION</CODE> request has been -processed by the forms driver. <P> - -<H2><A NAME="fuser">Field User Pointer</A></H2> - -Each field structure contains one character pointer slot that is not used -by the forms library. It is intended to be used by applications to store -private per-field data. You can manipulate it with: - -<PRE> -int set_field_userptr(FIELD *field, /* field to alter */ - char *userptr); /* mode to set */ - -char *field_userptr(FIELD *field); /* fetch mode of field */ -</PRE> - -(Properly, this user pointer field ought to have <CODE>(void *)</CODE> type. -The <CODE>(char *)</CODE> type is retained for System V compatibility.) <P> - -It is valid to set the user pointer of the default field (with a -<CODE>set_field_userptr()</CODE> call passed a NULL field pointer.) -When a new field is created, the default-field user pointer is copied -to initialize the new field's user pointer. <P> - -<H2><A NAME="fdynamic">Variable-Sized Fields</A></H2> - -Normally, a field is fixed at the size specified for it at creation -time. If, however, you turn off its O_STATIC bit, it becomes -<DFN>dynamic</DFN> and will automatically resize itself to accommodate -data as it is entered. If the field has extra buffers associated with it, -they will grow right along with the main input buffer. <P> - -A one-line dynamic field will have a fixed height (1) but variable -width, scrolling horizontally to display data within the field area as -originally dimensioned and located. A multi-line dynamic field will -have a fixed width, but variable height (number of rows), scrolling -vertically to display data within the field area as originally -dimensioned and located. <P> - -Normally, a dynamic field is allowed to grow without limit. But it is -possible to set an upper limit on the size of a dynamic field. You do -it with this function: <P> - -<PRE> -int set_max_field(FIELD *field, /* field to alter (may not be NULL) */ - int max_size); /* upper limit on field size */ -</PRE> - -If the field is one-line, <CODE>max_size</CODE> is taken to be a column size -limit; if it is multi-line, it is taken to be a line size limit. To disable -any limit, use an argument of zero. The growth limit can be changed whether -or not the O_STATIC bit is on, but has no effect until it is. <P> - -The following properties of a field change when it becomes dynamic: - -<UL> -<LI>If there is no growth limit, there is no final position of the field; -therefore <CODE>O_AUTOSKIP</CODE> and <CODE>O_NL_OVERLOAD</CODE> are ignored. -<LI>Field justification will be ignored (though whatever justification is -set up will be retained internally and can be queried). -<LI>The <CODE>dup_field()</CODE> and <CODE>link_field()</CODE> calls copy -dynamic-buffer sizes. If the <CODE>O_STATIC</CODE> option is set on one of a -collection of links, buffer resizing will occur only when the field is -edited through that link. -<LI>The call <CODE>field_info()</CODE> will retrieve the original static size of -the field; use <CODE>dynamic_field_info()</CODE> to get the actual dynamic size. -</UL> - -<H2><A NAME="fvalidation">Field Validation</A></H2> - -By default, a field will accept any data that will fit in its input buffer. -However, it is possible to attach a validation type to a field. If you do -this, any attempt to leave the field while it contains data that doesn't -match the validation type will fail. Some validation types also have a -character-validity check for each time a character is entered in the field. <P> - -A field's validation check (if any) is not called when -<CODE>set_field_buffer()</CODE> modifies the input buffer, nor when that buffer -is changed through a linked field. <P> - -The <CODE>form</CODE> library provides a rich set of pre-defined validation -types, and gives you the capability to define custom ones of your own. You -can examine and change field validation attributes with the following -functions: <P> - -<PRE> -int set_field_type(FIELD *field, /* field to alter */ - FIELDTYPE *ftype, /* type to associate */ - ...); /* additional arguments*/ - -FIELDTYPE *field_type(FIELD *field); /* field to query */ -</PRE> - -The validation type of a field is considered an attribute of the field. As -with other field attributes, Also, doing <CODE>set_field_type()</CODE> with a -<CODE>NULL</CODE> field default will change the system default for validation of -newly-created fields. <P> - -Here are the pre-defined validation types: <P> - -<H3><A NAME="ftype_alpha">TYPE_ALPHA</A></H3> - -This field type accepts alphabetic data; no blanks, no digits, no special -characters (this is checked at character-entry time). It is set up with: <P> - -<PRE> -int set_field_type(FIELD *field, /* field to alter */ - TYPE_ALPHA, /* type to associate */ - int width); /* maximum width of field */ -</PRE> - -The <CODE>width</CODE> argument sets a minimum width of data. Typically -you'll want to set this to the field width; if it's greater than the -field width, the validation check will always fail. A minimum width -of zero makes field completion optional. <P> - -<H3><A NAME="ftype_alnum">TYPE_ALNUM</A></H3> - -This field type accepts alphabetic data and digits; no blanks, no special -characters (this is checked at character-entry time). It is set up with: <P> - -<PRE> -int set_field_type(FIELD *field, /* field to alter */ - TYPE_ALNUM, /* type to associate */ - int width); /* maximum width of field */ -</PRE> - -The <CODE>width</CODE> argument sets a minimum width of data. As with -TYPE_ALPHA, typically you'll want to set this to the field width; if it's -greater than the field width, the validation check will always fail. A -minimum width of zero makes field completion optional. <P> - -<H3><A NAME="ftype_enum">TYPE_ENUM</A></H3> - -This type allows you to restrict a field's values to be among a specified -set of string values (for example, the two-letter postal codes for U.S. -states). It is set up with: <P> - -<PRE> -int set_field_type(FIELD *field, /* field to alter */ - TYPE_ENUM, /* type to associate */ - char **valuelist; /* list of possible values */ - int checkcase; /* case-sensitive? */ - int checkunique); /* must specify uniquely? */ -</PRE> - -The <CODE>valuelist</CODE> parameter must point at a NULL-terminated list of -valid strings. The <CODE>checkcase</CODE> argument, if true, makes comparison -with the string case-sensitive. <P> - -When the user exits a TYPE_ENUM field, the validation procedure tries to -complete the data in the buffer to a valid entry. If a complete choice string -has been entered, it is of course valid. But it is also possible to enter a -prefix of a valid string and have it completed for you. <P> - -By default, if you enter such a prefix and it matches more than one value -in the string list, the prefix will be completed to the first matching -value. But the <CODE>checkunique</CODE> argument, if true, requires prefix -matches to be unique in order to be valid. <P> - -The <CODE>REQ_NEXT_CHOICE</CODE> and <CODE>REQ_PREV_CHOICE</CODE> input requests -can be particularly useful with these fields. <P> - -<H3><A NAME="ftype_integer">TYPE_INTEGER</A></H3> - -This field type accepts an integer. It is set up as follows: <P> - -<PRE> -int set_field_type(FIELD *field, /* field to alter */ - TYPE_INTEGER, /* type to associate */ - int padding, /* # places to zero-pad to */ - int vmin, int vmax); /* valid range */ -</PRE> - -Valid characters consist of an optional leading minus and digits. -The range check is performed on exit. If the range maximum is less -than or equal to the minimum, the range is ignored. <P> - -If the value passes its range check, it is padded with as many leading -zero digits as necessary to meet the padding argument. <P> - -A <CODE>TYPE_INTEGER</CODE> value buffer can conveniently be interpreted -with the C library function <CODE>atoi(3)</CODE>. - -<H3><A NAME="ftype_numeric">TYPE_NUMERIC</A></H3> - -This field type accepts a decimal number. It is set up as follows: <P> - -<PRE> -int set_field_type(FIELD *field, /* field to alter */ - TYPE_NUMERIC, /* type to associate */ - int padding, /* # places of precision */ - double vmin, double vmax); /* valid range */ -</PRE> - -Valid characters consist of an optional leading minus and digits. possibly -including a decimal point. If your system supports locale's, the decimal point -character used must be the one defined by your locale. The range check is -performed on exit. If the range maximum is less than or equal to the minimum, -the range is ignored. <P> - -If the value passes its range check, it is padded with as many trailing -zero digits as necessary to meet the padding argument. <P> - -A <CODE>TYPE_NUMERIC</CODE> value buffer can conveniently be interpreted -with the C library function <CODE>atof(3)</CODE>. - -<H3><A NAME="ftype_regexp">TYPE_REGEXP</A></H3> - -This field type accepts data matching a regular expression. It is set up -as follows: <P> - -<PRE> -int set_field_type(FIELD *field, /* field to alter */ - TYPE_REGEXP, /* type to associate */ - char *regexp); /* expression to match */ -</PRE> - -The syntax for regular expressions is that of <CODE>regcomp(3)</CODE>. -The check for regular-expression match is performed on exit. - -<H2><A NAME="fbuffer">Direct Field Buffer Manipulation</A></H2> - -The chief attribute of a field is its buffer contents. When a form has -been completed, your application usually needs to know the state of each -field buffer. You can find this out with: <P> - -<PRE> -char *field_buffer(FIELD *field, /* field to query */ - int bufindex); /* number of buffer to query */ -</PRE> - -Normally, the state of the zero-numbered buffer for each field is set by -the user's editing actions on that field. It's sometimes useful to be able -to set the value of the zero-numbered (or some other) buffer from your -application: - -<PRE> -int set_field_buffer(FIELD *field, /* field to alter */ - int bufindex, /* number of buffer to alter */ - char *value); /* string value to set */ -</PRE> - -If the field is not large enough and cannot be resized to a sufficiently -large size to contain the specified value, the value will be truncated -to fit. <P> - -Calling <CODE>field_buffer()</CODE> with a null field pointer will raise an -error. Calling <CODE>field_buffer()</CODE> on a field not currently selected -for input will return a correct value. Calling <CODE>field_buffer()</CODE> on a -field that is currently selected for input may not necessarily give a -correct field buffer value, because entered data isn't necessarily copied to -buffer zero before the exit validation check. - -To guarantee that the returned buffer value reflects on-screen reality, -call <CODE>field_buffer()</CODE> either (1) in the field's exit validation -check routine, (2) from the field's or form's initialization or termination -hooks, or (3) just after a <CODE>REQ_VALIDATION</CODE> request has been processed -by the forms driver. <P> - -<H2><A NAME="formattrs">Attributes of Forms</A></H2> - -As with field attributes, form attributes inherit a default from a -system default form structure. These defaults can be queried or set by -of these functions using a form-pointer argument of <CODE>NULL</CODE>. <P> - -The principal attribute of a form is its field list. You can query -and change this list with: <P> - -<PRE> -int set_form_fields(FORM *form, /* form to alter */ - FIELD **fields); /* fields to connect */ - -char *form_fields(FORM *form); /* fetch fields of form */ - -int field_count(FORM *form); /* count connect fields */ -</PRE> - -The second argument of <CODE>set_form_fields()</CODE> may be a -NULL-terminated field pointer array like the one required by -<CODE>new_form()</CODE>. In that case, the old fields of the form are -disconnected but not freed (and eligible to be connected to other -forms), then the new fields are connected. <P> - -It may also be null, in which case the old fields are disconnected -(and not freed) but no new ones are connected. <P> - -The <CODE>field_count()</CODE> function simply counts the number of fields -connected to a given from. It returns -1 if the form-pointer argument -is NULL. <P> - -<H2><A NAME="fdisplay">Control of Form Display</A></H2> - -In the overview section, you saw that to display a form you normally -start by defining its size (and fields), posting it, and refreshing -the screen. There is an hidden step before posting, which is the -association of the form with a frame window (actually, a pair of -windows) within which it will be displayed. By default, the forms -library associates every form with the full-screen window -<CODE>stdscr</CODE>. <P> - -By making this step explicit, you can associate a form with a declared -frame window on your screen display. This can be useful if you want to -adapt the form display to different screen sizes, dynamically tile -forms on the screen, or use a form as part of an interface layout -managed by <A HREF="#panels">panels</A>. <P> - -The two windows associated with each form have the same functions as -their analogues in the <A HREF="#menu">menu library</A>. Both these -windows are painted when the form is posted and erased when the form -is unposted. <P> - -The outer or frame window is not otherwise touched by the form -routines. It exists so the programmer can associate a title, a -border, or perhaps help text with the form and have it properly -refreshed or erased at post/unpost time. The inner window or subwindow -is where the current form page is actually displayed. <P> - -In order to declare your own frame window for a form, you'll need to -know the size of the form's bounding rectangle. You can get this -information with: <P> - -<PRE> -int scale_form(FORM *form, /* form to query */ - int *rows, /* form rows */ - int *cols); /* form cols */ -</PRE> - -The form dimensions are passed back in the locations pointed to by -the arguments. Once you have this information, you can use it to -declare of windows, then use one of these functions: - -<PRE> -int set_form_win(FORM *form, /* form to alter */ - WINDOW *win); /* frame window to connect */ - -WINDOW *form_win(FORM *form); /* fetch frame window of form */ - -int set_form_sub(FORM *form, /* form to alter */ - WINDOW *win); /* form subwindow to connect */ - -WINDOW *form_sub(FORM *form); /* fetch form subwindow of form */ -</PRE> - -Note that curses operations, including <CODE>refresh()</CODE>, on the form, -should be done on the frame window, not the form subwindow. <P> - -It is possible to check from your application whether all of a -scrollable field is actually displayed within the menu subwindow. Use -these functions: <P> - -<PRE> -int data_ahead(FORM *form); /* form to be queried */ - -int data_behind(FORM *form); /* form to be queried */ -</PRE> - -The function <CODE>data_ahead()</CODE> returns TRUE if (a) the current -field is one-line and has undisplayed data off to the right, (b) the current -field is multi-line and there is data off-screen below it. <P> - -The function <CODE>data_behind()</CODE> returns TRUE if the first (upper -left hand) character position is off-screen (not being displayed). <P> - -Finally, there is a function to restore the form window's cursor to the -value expected by the forms driver: <P> - -<PRE> -int pos_form_cursor(FORM *) /* form to be queried */ -</PRE> - -If your application changes the form window cursor, call this function before -handing control back to the forms driver in order to re-synchronize it. <P> - -<H2><A NAME="fdriver">Input Processing in the Forms Driver</A></H2> - -The function <CODE>form_driver()</CODE> handles virtualized input requests -for form navigation, editing, and validation requests, just as -<CODE>menu_driver</CODE> does for menus (see the section on <A -HREF="#minput">menu input handling</A>). <P> - -<PRE> -int form_driver(FORM *form, /* form to pass input to */ - int request); /* form request code */ -</PRE> - -Your input virtualization function needs to take input and then convert it -to either an alphanumeric character (which is treated as data to be -entered in the currently-selected field), or a forms processing request. <P> - -The forms driver provides hooks (through input-validation and -field-termination functions) with which your application code can check -that the input taken by the driver matched what was expected. <P> - -<H3><A NAME="fpage">Page Navigation Requests</A></H3> - -These requests cause page-level moves through the form, -triggering display of a new form screen. <P> - -<DL> -<DT> <CODE>REQ_NEXT_PAGE</CODE> -<DD> Move to the next form page. -<DT> <CODE>REQ_PREV_PAGE</CODE> -<DD> Move to the previous form page. -<DT> <CODE>REQ_FIRST_PAGE</CODE> -<DD> Move to the first form page. -<DT> <CODE>REQ_LAST_PAGE</CODE> -<DD> Move to the last form page. -</DL> - -These requests treat the list as cyclic; that is, <CODE>REQ_NEXT_PAGE</CODE> -from the last page goes to the first, and <CODE>REQ_PREV_PAGE</CODE> from -the first page goes to the last. <P> - -<H3><A NAME="#ffield">Inter-Field Navigation Requests</A></H3> - -These requests handle navigation between fields on the same page. <P> - -<DL> -<DT> <CODE>REQ_NEXT_FIELD</CODE> -<DD> Move to next field. -<DT> <CODE>REQ_PREV_FIELD</CODE> -<DD> Move to previous field. -<DT> <CODE>REQ_FIRST_FIELD</CODE> -<DD> Move to the first field. -<DT> <CODE>REQ_LAST_FIELD</CODE> -<DD> Move to the last field. -<P> -<DT> <CODE>REQ_SNEXT_FIELD</CODE> -<DD> Move to sorted next field. -<DT> <CODE>REQ_SPREV_FIELD</CODE> -<DD> Move to sorted previous field. -<DT> <CODE>REQ_SFIRST_FIELD</CODE> -<DD> Move to the sorted first field. -<DT> <CODE>REQ_SLAST_FIELD</CODE> -<DD> Move to the sorted last field. -<P> -<DT> <CODE>REQ_LEFT_FIELD</CODE> -<DD> Move left to field. -<DT> <CODE>REQ_RIGHT_FIELD</CODE> -<DD> Move right to field. -<DT> <CODE>REQ_UP_FIELD</CODE> -<DD> Move up to field. -<DT> <CODE>REQ_DOWN_FIELD</CODE> -<DD> Move down to field. -</DL> - -These requests treat the list of fields on a page as cyclic; that is, -<CODE>REQ_NEXT_FIELD</CODE> from the last field goes to the first, and -<CODE>REQ_PREV_FIELD</CODE> from the first field goes to the last. The -order of the fields for these (and the <CODE>REQ_FIRST_FIELD</CODE> and -<CODE>REQ_LAST_FIELD</CODE> requests) is simply the order of the field -pointers in the form array (as set up by <CODE>new_form()</CODE> or -<CODE>set_form_fields()</CODE> <P> - -It is also possible to traverse the fields as if they had been sorted in -screen-position order, so the sequence goes left-to-right and top-to-bottom. -To do this, use the second group of four sorted-movement requests. <P> - -Finally, it is possible to move between fields using visual directions up, -down, right, and left. To accomplish this, use the third group of four -requests. Note, however, that the position of a form for purposes of these -requests is its upper-left corner. <P> - -For example, suppose you have a multi-line field B, and two -single-line fields A and C on the same line with B, with A to the left -of B and C to the right of B. A <CODE>REQ_MOVE_RIGHT</CODE> from A will -go to B only if A, B, and C <EM>all</EM> share the same first line; -otherwise it will skip over B to C. <P> - -<H3><A NAME="#fifield">Intra-Field Navigation Requests</A></H3> - -These requests drive movement of the edit cursor within the currently -selected field. <P> - -<DL> -<DT> <CODE>REQ_NEXT_CHAR</CODE> -<DD> Move to next character. -<DT> <CODE>REQ_PREV_CHAR</CODE> -<DD> Move to previous character. -<DT> <CODE>REQ_NEXT_LINE</CODE> -<DD> Move to next line. -<DT> <CODE>REQ_PREV_LINE</CODE> -<DD> Move to previous line. -<DT> <CODE>REQ_NEXT_WORD</CODE> -<DD> Move to next word. -<DT> <CODE>REQ_PREV_WORD</CODE> -<DD> Move to previous word. -<DT> <CODE>REQ_BEG_FIELD</CODE> -<DD> Move to beginning of field. -<DT> <CODE>REQ_END_FIELD</CODE> -<DD> Move to end of field. -<DT> <CODE>REQ_BEG_LINE</CODE> -<DD> Move to beginning of line. -<DT> <CODE>REQ_END_LINE</CODE> -<DD> Move to end of line. -<DT> <CODE>REQ_LEFT_CHAR</CODE> -<DD> Move left in field. -<DT> <CODE>REQ_RIGHT_CHAR</CODE> -<DD> Move right in field. -<DT> <CODE>REQ_UP_CHAR</CODE> -<DD> Move up in field. -<DT> <CODE>REQ_DOWN_CHAR</CODE> -<DD> Move down in field. -</DL> - -Each <EM>word</EM> is separated from the previous and next characters -by whitespace. The commands to move to beginning and end of line or field -look for the first or last non-pad character in their ranges. <P> - -<H3><A NAME="fscroll">Scrolling Requests</A></H3> - -Fields that are dynamic and have grown and fields explicitly created -with offscreen rows are scrollable. One-line fields scroll horizontally; -multi-line fields scroll vertically. Most scrolling is triggered by -editing and intra-field movement (the library scrolls the field to keep the -cursor visible). It is possible to explicitly request scrolling with the -following requests: -<P> - -<DL> -<DT> <CODE>REQ_SCR_FLINE</CODE> -<DD> Scroll vertically forward a line. -<DT> <CODE>REQ_SCR_BLINE</CODE> -<DD> Scroll vertically backward a line. -<DT> <CODE>REQ_SCR_FPAGE</CODE> -<DD> Scroll vertically forward a page. -<DT> <CODE>REQ_SCR_BPAGE</CODE> -<DD> Scroll vertically backward a page. -<DT> <CODE>REQ_SCR_FHPAGE</CODE> -<DD> Scroll vertically forward half a page. -<DT> <CODE>REQ_SCR_BHPAGE</CODE> -<DD> Scroll vertically backward half a page. -<DT> <CODE>REQ_SCR_FCHAR</CODE> -<DD> Scroll horizontally forward a character. -<DT> <CODE>REQ_SCR_BCHAR</CODE> -<DD> Scroll horizontally backward a character. -<DT> <CODE>REQ_SCR_HFLINE</CODE> -<DD> Scroll horizontally one field width forward. -<DT> <CODE>REQ_SCR_HBLINE</CODE> -<DD> Scroll horizontally one field width backward. -<DT> <CODE>REQ_SCR_HFHALF</CODE> -<DD> Scroll horizontally one half field width forward. -<DT> <CODE>REQ_SCR_HBHALF</CODE> -<DD> Scroll horizontally one half field width backward. -</DL> - -For scrolling purposes, a <EM>page</EM> of a field is the height -of its visible part. <P> - -<H3><A NAME="fedit">Editing Requests</A></H3> - -When you pass the forms driver an ASCII character, it is treated as a -request to add the character to the field's data buffer. Whether this -is an insertion or a replacement depends on the field's edit mode -(insertion is the default. <P> - -The following requests support editing the field and changing the edit -mode: <P> - -<DL> -<DT> <CODE>REQ_INS_MODE</CODE> -<DD> Set insertion mode. -<DT> <CODE>REQ_OVL_MODE</CODE> -<DD> Set overlay mode. -<DT> <CODE>REQ_NEW_LINE</CODE> -<DD> New line request (see below for explanation). -<DT> <CODE>REQ_INS_CHAR</CODE> -<DD> Insert space at character location. -<DT> <CODE>REQ_INS_LINE</CODE> -<DD> Insert blank line at character location. -<DT> <CODE>REQ_DEL_CHAR</CODE> -<DD> Delete character at cursor. -<DT> <CODE>REQ_DEL_PREV</CODE> -<DD> Delete previous word at cursor. -<DT> <CODE>REQ_DEL_LINE</CODE> -<DD> Delete line at cursor. -<DT> <CODE>REQ_DEL_WORD</CODE> -<DD> Delete word at cursor. -<DT> <CODE>REQ_CLR_EOL</CODE> -<DD> Clear to end of line. -<DT> <CODE>REQ_CLR_EOF</CODE> -<DD> Clear to end of field. -<DT> <CODE>REQ_CLEAR_FIELD</CODE> -<DD> Clear entire field. -</DL> - -The behavior of the <CODE>REQ_NEW_LINE</CODE> and <CODE>REQ_DEL_PREV</CODE> requests -is complicated and partly controlled by a pair of forms options. -The special cases are triggered when the cursor is at the beginning of -a field, or on the last line of the field. <P> - -First, we consider <CODE>REQ_NEW_LINE</CODE>: <P> - -The normal behavior of <CODE>REQ_NEW_LINE</CODE> in insert mode is to break the -current line at the position of the edit cursor, inserting the portion of -the current line after the cursor as a new line following the current -and moving the cursor to the beginning of that new line (you may think -of this as inserting a newline in the field buffer). <P> - -The normal behavior of <CODE>REQ_NEW_LINE</CODE> in overlay mode is to clear the -current line from the position of the edit cursor to end of line. -The cursor is then moved to the beginning of the next line. <P> - -However, <CODE>REQ_NEW_LINE</CODE> at the beginning of a field, or on the -last line of a field, instead does a <CODE>REQ_NEXT_FIELD</CODE>. -<CODE>O_NL_OVERLOAD</CODE> option is off, this special action is -disabled. <P> - -Now, let us consider <CODE>REQ_DEL_PREV</CODE>: <P> - -The normal behavior of <CODE>REQ_DEL_PREV</CODE> is to delete the previous -character. If insert mode is on, and the cursor is at the start of a -line, and the text on that line will fit on the previous one, it -instead appends the contents of the current line to the previous one -and deletes the current line (you may think of this as deleting a -newline from the field buffer). <P> - -However, <CODE>REQ_DEL_PREV</CODE> at the beginning of a field is instead -treated as a <CODE>REQ_PREV_FIELD</CODE>. <P> If the -<CODE>O_BS_OVERLOAD</CODE> option is off, this special action is -disabled and the forms driver just returns <CODE>E_REQUEST_DENIED</CODE>. <P> - -See <A HREF="#frmoptions">Form Options</A> for discussion of how to set -and clear the overload options. <P> - -<H3><A NAME="forder">Order Requests</A></H3> - -If the type of your field is ordered, and has associated functions -for getting the next and previous values of the type from a given value, -there are requests that can fetch that value into the field buffer: <P> - -<DL> -<DT> <CODE>REQ_NEXT_CHOICE</CODE> -<DD> Place the successor value of the current value in the buffer. -<DT> <CODE>REQ_PREV_CHOICE</CODE> -<DD> Place the predecessor value of the current value in the buffer. -</DL> - -Of the built-in field types, only <CODE>TYPE_ENUM</CODE> has built-in successor -and predecessor functions. When you define a field type of your own -(see <A HREF="#fcustom">Custom Validation Types</A>), you can associate -our own ordering functions. <P> - -<H3><A NAME="fappcmds">Application Commands</A></H3> - -Form requests are represented as integers above the <CODE>curses</CODE> value -greater than <CODE>KEY_MAX</CODE> and less than or equal to the constant -<CODE>MAX_COMMAND</CODE>. If your input-virtualization routine returns a -value above <CODE>MAX_COMMAND</CODE>, the forms driver will ignore it. <P> - -<H2><A NAME="fhooks">Field Change Hooks</A></H2> - -It is possible to set function hooks to be executed whenever the -current field or form changes. Here are the functions that support this: <P> - -<PRE> -typedef void (*HOOK)(); /* pointer to function returning void */ - -int set_form_init(FORM *form, /* form to alter */ - HOOK hook); /* initialization hook */ - -HOOK form_init(FORM *form); /* form to query */ - -int set_form_term(FORM *form, /* form to alter */ - HOOK hook); /* termination hook */ - -HOOK form_term(FORM *form); /* form to query */ - -int set_field_init(FORM *form, /* form to alter */ - HOOK hook); /* initialization hook */ - -HOOK field_init(FORM *form); /* form to query */ - -int set_field_term(FORM *form, /* form to alter */ - HOOK hook); /* termination hook */ - -HOOK field_term(FORM *form); /* form to query */ -</PRE> - -These functions allow you to either set or query four different hooks. -In each of the set functions, the second argument should be the -address of a hook function. These functions differ only in the timing -of the hook call. <P> - -<DL> -<DT> form_init -<DD> This hook is called when the form is posted; also, just after -each page change operation. -<DT> field_init -<DD> This hook is called when the form is posted; also, just after -each field change -<DT> field_term -<DD> This hook is called just after field validation; that is, just before -the field is altered. It is also called when the form is unposted. <P> -<DT> form_term -<DD> This hook is called when the form is unposted; also, just before -each page change operation. -</DL> - -Calls to these hooks may be triggered -<OL> -<LI>When user editing requests are processed by the forms driver -<LI>When the current page is changed by <CODE>set_current_field()</CODE> call -<LI>When the current field is changed by a <CODE>set_form_page()</CODE> call -</OL> - -See <A NAME="ffocus">Field Change Commands</A> for discussion of the latter -two cases. <P> - -You can set a default hook for all fields by passing one of the set functions -a NULL first argument. <P> - -You can disable any of these hooks by (re)setting them to NULL, the default -value. <P> - -<H2><A HREF="#ffocus">Field Change Commands</A></H2> - -Normally, navigation through the form will be driven by the user's -input requests. But sometimes it is useful to be able to move the -focus for editing and viewing under control of your application, or -ask which field it currently is in. The following functions help you -accomplish this: <P> - -<PRE> -int set_current_field(FORM *form, /* form to alter */ - FIELD *field); /* field to shift to */ - -FIELD *current_field(FORM *form); /* form to query */ - -int field_index(FORM *form, /* form to query */ - FIELD *field); /* field to get index of */ -</PRE> - -The function <CODE>field_index()</CODE> returns the index of the given field -in the given form's field array (the array passed to <CODE>new_form()</CODE> or -<CODE>set_form_fields()</CODE>). <P> - -The initial current field of a form is the first active field on the -first page. The function <CODE>set_form_fields()</CODE> resets this.<P> - -It is also possible to move around by pages. <P> - -<PRE> -int set_form_page(FORM *form, /* form to alter */ - int page); /* page to go to (0-origin) */ - -int form_page(FORM *form); /* return form's current page */ -</PRE> - -The initial page of a newly-created form is 0. The function -<CODE>set_form_fields()</CODE> resets this. <P> - -<H2><A NAME="frmoptions">Form Options</A></H2> - -Like fields, forms may have control option bits. They can be changed -or queried with these functions: <P> - -<PRE> -int set_form_opts(FORM *form, /* form to alter */ - int attr); /* attribute to set */ - -int form_opts_on(FORM *form, /* form to alter */ - int attr); /* attributes to turn on */ - -int form_opts_off(FORM *form, /* form to alter */ - int attr); /* attributes to turn off */ - -int form_opts(FORM *form); /* form to query */ -</PRE> - -By default, all options are on. Here are the available option bits: - -<DL> -<DT> O_NL_OVERLOAD -<DD> Enable overloading of <CODE>REQ_NEW_LINE</CODE> as described in <A -NAME="fedit">Editing Requests</A>. The value of this option is -ignored on dynamic fields that have not reached their size limit; -these have no last line, so the circumstances for triggering a -<CODE>REQ_NEXT_FIELD</CODE> never arise. -<DT> O_BS_OVERLOAD -<DD> Enable overloading of <CODE>REQ_DEL_PREV</CODE> as described in -<A NAME="fedit">Editing Requests</A>. -</DL> - -The option values are bit-masks and can be composed with logical-or in -the obvious way. <P> - -<H2><A NAME="fcustom">Custom Validation Types</A></H2> - -The <CODE>form</CODE> library gives you the capability to define custom -validation types of your own. Further, the optional additional arguments -of <CODE>set_field_type</CODE> effectively allow you to parameterize validation -types. Most of the complications in the validation-type interface have to -do with the handling of the additional arguments within custom validation -functions. <P> - -<H3><A NAME="flinktypes">Union Types</A></H3> - -The simplest way to create a custom data type is to compose it from two -preexisting ones: <P> - -<PRE> -FIELD *link_fieldtype(FIELDTYPE *type1, - FIELDTYPE *type2); -</PRE> - -This function creates a field type that will accept any of the values -legal for either of its argument field types (which may be either -predefined or programmer-defined). - -If a <CODE>set_field_type()</CODE> call later requires arguments, the new -composite type expects all arguments for the first type, than all arguments -for the second. Order functions (see <A HREF="#forder">Order Requests</A>) -associated with the component types will work on the composite; what it does -is check the validation function for the first type, then for the second, to -figure what type the buffer contents should be treated as. <P> - -<H3><A NAME="fnewtypes">New Field Types</A></H3> - -To create a field type from scratch, you need to specify one or both of the -following things: <P> - -<UL> -<LI>A character-validation function, to check each character as it is entered. -<LI>A field-validation function to be applied on exit from the field. -</UL> - -Here's how you do that: <P> -<PRE> -typedef int (*HOOK)(); /* pointer to function returning int */ - -FIELDTYPE *new_fieldtype(HOOK f_validate, /* field validator */ - HOOK c_validate) /* character validator */ - - -int free_fieldtype(FIELDTYPE *ftype); /* type to free */ -</PRE> - -At least one of the arguments of <CODE>new_fieldtype()</CODE> must be -non-NULL. The forms driver will automatically call the new type's -validation functions at appropriate points in processing a field of -the new type. <P> - -The function <CODE>free_fieldtype()</CODE> deallocates the argument -fieldtype, freeing all storage associated with it. <P> - -Normally, a field validator is called when the user attempts to -leave the field. Its first argument is a field pointer, from which it -can get to field buffer 0 and test it. If the function returns TRUE, -the operation succeeds; if it returns FALSE, the edit cursor stays in -the field. <P> - -A character validator gets the character passed in as a first argument. -It too should return TRUE if the character is valid, FALSE otherwise. <P> - -<H3><A NAME="fcheckargs">Validation Function Arguments</A></H3> - -Your field- and character- validation functions will be passed a -second argument as well. This second argument is the address of a -structure (which we'll call a <EM>pile</EM>) built from any of the -field-type-specific arguments passed to <CODE>set_field_type()</CODE>. If -no such arguments are defined for the field type, this pile pointer -argument will be NULL. <P> - -In order to arrange for such arguments to be passed to your validation -functions, you must associate a small set of storage-management functions -with the type. The forms driver will use these to synthesize a pile -from the trailing arguments of each <CODE>set_field_type()</CODE> argument, and -a pointer to the pile will be passed to the validation functions. <P> - -Here is how you make the association: <P> - -<PRE> -typedef char *(*PTRHOOK)(); /* pointer to function returning (char *) */ -typedef void (*VOIDHOOK)(); /* pointer to function returning void */ - -int set_fieldtype_arg(FIELDTYPE *type, /* type to alter */ - PTRHOOK make_str, /* make structure from args */ - PTRHOOK copy_str, /* make copy of structure */ - VOIDHOOK free_str); /* free structure storage */ -</PRE> - -Here is how the storage-management hooks are used: <P> - -<DL> -<DT> <CODE>make_str</CODE> -<DD> This function is called by <CODE>set_field_type()</CODE>. It gets one -argument, a <CODE>va_list</CODE> of the type-specific arguments passed to -<CODE>set_field_type()</CODE>. It is expected to return a pile pointer to a data -structure that encapsulates those arguments. -<DT> <CODE>copy_str</CODE> -<DD> This function is called by form library functions that allocate new -field instances. It is expected to take a pile pointer, copy the pile -to allocated storage, and return the address of the pile copy. -<DT> <CODE>free_str</CODE> -<DD> This function is called by field- and type-deallocation routines in the -library. It takes a pile pointer argument, and is expected to free the -storage of that pile. -</DL> - -The <CODE>make_str</CODE> and <CODE>copy_str</CODE> functions may return NULL to -signal allocation failure. The library routines will that call them will -return error indication when this happens. Thus, your validation functions -should never see a NULL file pointer and need not check specially for it. <P> - -<H3><A NAME="fcustorder">Order Functions For Custom Types</A></H3> - -Some custom field types are simply ordered in the same well-defined way -that <CODE>TYPE_ENUM</CODE> is. For such types, it is possible to define -successor and predecessor functions to support the <CODE>REQ_NEXT_CHOICE</CODE> -and <CODE>REQ_PREV_CHOICE</CODE> requests. Here's how: <P> - -<PRE> -typedef int (*INTHOOK)(); /* pointer to function returning int */ - -int set_fieldtype_arg(FIELDTYPE *type, /* type to alter */ - INTHOOK succ, /* get successor value */ - INTHOOK pred); /* get predecessor value */ -</PRE> - -The successor and predecessor arguments will each be passed two arguments; -a field pointer, and a pile pointer (as for the validation functions). They -are expected to use the function <CODE>field_buffer()</CODE> to read the -current value, and <CODE>set_field_buffer()</CODE> on buffer 0 to set the next -or previous value. Either hook may return TRUE to indicate success (a -legal next or previous value was set) or FALSE to indicate failure. <P> - -<H3><A NAME="fcustprobs">Avoiding Problems</A></H3> - -The interface for defining custom types is complicated and tricky. -Rather than attempting to create a custom type entirely from scratch, -you should start by studying the library source code for whichever of -the pre-defined types seems to be closest to what you want. <P> - -Use that code as a model, and evolve it towards what you really want. -You will avoid many problems and annoyances that way. The code -in the <CODE>ncurses</CODE> library has been specifically exempted from -the package copyright to support this. <P> - -If your custom type defines order functions, have do something intuitive -with a blank field. A useful convention is to make the successor of a -blank field the types minimum value, and its predecessor the maximum. -</BODY> -</HTML> diff --git a/contrib/ncurses/misc/run_tic.sh b/contrib/ncurses/misc/run_tic.sh deleted file mode 100755 index cdb6a5ea24bc..000000000000 --- a/contrib/ncurses/misc/run_tic.sh +++ /dev/null @@ -1,170 +0,0 @@ -#!/bin/sh -############################################################################## -# Copyright (c) 1998,2000 Free Software Foundation, Inc. # -# # -# Permission is hereby granted, free of charge, to any person obtaining a # -# copy of this software and associated documentation files (the "Software"), # -# to deal in the Software without restriction, including without limitation # -# the rights to use, copy, modify, merge, publish, distribute, distribute # -# with modifications, sublicense, and/or sell copies of the Software, and to # -# permit persons to whom the Software is furnished to do so, subject to the # -# following conditions: # -# # -# The above copyright notice and this permission notice shall be included in # -# all copies or substantial portions of the Software. # -# # -# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # -# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # -# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL # -# THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # -# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING # -# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER # -# DEALINGS IN THE SOFTWARE. # -# # -# Except as contained in this notice, the name(s) of the above copyright # -# holders shall not be used in advertising or otherwise to promote the sale, # -# use or other dealings in this Software without prior written # -# authorization. # -############################################################################## -# -# Author: Thomas E. Dickey <dickey@clark.net> 1996 -# -# $Id: run_tic.sh,v 1.12 2000/07/01 19:25:13 tom Exp $ -# This script is used to install terminfo.src using tic. We use a script -# because the path checking is too awkward to do in a makefile. -# -# Parameters: -# $1 = nominal directory in which to find 'tic', i.e., $(bindir). -# $2 = source-directory, i.e., $(srcdir) -# $3 = destination-directory path, i.e., $(ticdir) -# $4 = install-prefix, if any -# -# Assumes: -# The leaf directory names (bin, lib, shared, tabset, terminfo) -# -echo '** Building terminfo database, please wait...' -# -# Parameter parsing is primarily for debugging. The script is designed to -# be run from the misc/Makefile as -# make install.data -prefix=/usr/local -if test $# != 0 ; then - bindir=$1 - shift - PREFIX=`echo $bindir | sed -e 's/\/bin$//'` - test -n "$PREFIX" && test "x$PREFIX" != "x$bindir" && prefix=$PREFIX -else - bindir=$prefix/bin -fi - -if test $# != 0 ; then - srcdir=$1 - shift -else - srcdir=. -fi - -if test $# != 0 ; then - ticdir=$1 - shift -else - ticdir=$prefix/share/terminfo -fi - -if test $# != 0 ; then - IP=$1 - shift -else - IP="" -fi - -# Allow tic to run either from the install-path, or from the build-directory -case "$PATH" in -:*) PATH=../progs:$IP$bindir$PATH ;; -*) PATH=../progs:$IP$bindir:$PATH ;; -esac -export PATH - -# -# set another env var that doesn't get reset when `shlib' runs, so `shlib' uses -# the PATH we just set. -# -NEWPATH=$PATH -export NEWPATH -PROG_BIN_DIR=$IP$bindir -export PROG_BIN_DIR - -TERMINFO=$IP$ticdir ; export TERMINFO -umask 022 - -# Construct the name of the old (obsolete) pathname, e.g., /usr/lib/terminfo. -TICDIR=`echo $TERMINFO | sed -e 's/\/share\//\/lib\//'` - -# Remove the old terminfo stuff; we don't care if it existed before, and it -# would generate a lot of confusing error messages if we tried to overwrite it. -# We explicitly remove its contents rather than the directory itself, in case -# the directory is actually a symbolic link. -( rm -fr $TERMINFO/[0-9A-Za-z] 2>/dev/null ) - -# If we're not installing into /usr/share/, we'll have to adjust the location -# of the tabset files in terminfo.src (which are in a parallel directory). -TABSET=`echo $ticdir | sed -e 's/\/terminfo$/\/tabset/'` -SRC=$srcdir/terminfo.src -if test "x$TABSET" != "x/usr/share/tabset" ; then - echo '** adjusting tabset paths' - TMP=${TMPDIR-/tmp}/$$ - sed -e s:/usr/share/tabset:$TABSET:g $SRC >$TMP - trap "rm -f $TMP" 0 1 2 5 15 - SRC=$TMP -fi - -cat <<EOF -Running tic to install $TERMINFO ... - - You may see messages regarding unknown capabilities, e.g., AX. - These are extended terminal capabilities which can be compiled - using - tic -x - Read the INSTALL document before doing this - it can cause - problems for older ncurses applications. - -EOF -if ( $srcdir/shlib tic -s $SRC ) -then - echo '** built new '$TERMINFO -else - echo '? tic could not build '$TERMINFO - exit 1 -fi - -# Make a symbolic link to provide compatibility with applications that expect -# to find terminfo under /usr/lib. That is, we'll _try_ to do that. Not -# all systems support symbolic links, and those that do provide a variety -# of options for 'test'. -if test "$TICDIR" != "$TERMINFO" ; then - ( rm -f $TICDIR 2>/dev/null ) - if ( cd $TICDIR 2>/dev/null ) - then - cd $TICDIR - TICDIR=`pwd` - if test $TICDIR != $TERMINFO ; then - # Well, we tried. Some systems lie to us, so the - # installer will have to double-check. - echo "Verify if $TICDIR and $TERMINFO are the same." - echo "The new terminfo is in $TERMINFO; the other should be a link to it." - echo "Otherwise, remove $TICDIR and link it to $TERMINFO." - fi - else - cd $IP$prefix - # Construct a symbolic link that only assumes $ticdir has the - # same $prefix as the other installed directories. - RELATIVE=`echo $ticdir|sed -e 's:^'$prefix'/::'` - if test "$RELATIVE" != "$ticdir" ; then - RELATIVE=../`echo $ticdir|sed -e 's:^'$prefix'/::' -e 's:^/::'` - fi - if ( ln -s $RELATIVE $TICDIR ) - then - echo '** linked '$TICDIR' for compatibility' - fi - fi -fi |