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Diffstat (limited to 'contrib/bc/manuals/dc/EN.1')
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1 files changed, 359 insertions, 273 deletions
diff --git a/contrib/bc/manuals/dc/EN.1 b/contrib/bc/manuals/dc/EN.1 index d941c130e847..2d1c038754e9 100644 --- a/contrib/bc/manuals/dc/EN.1 +++ b/contrib/bc/manuals/dc/EN.1 @@ -1,7 +1,7 @@ .\" .\" SPDX-License-Identifier: BSD-2-Clause .\" -.\" Copyright (c) 2018-2021 Gavin D. Howard and contributors. +.\" Copyright (c) 2018-2025 Gavin D. Howard and contributors. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions are met: @@ -25,124 +25,82 @@ .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE .\" POSSIBILITY OF SUCH DAMAGE. .\" -.TH "DC" "1" "June 2022" "Gavin D. Howard" "General Commands Manual" +.TH "DC" "1" "August 2024" "Gavin D. Howard" "General Commands Manual" .nh .ad l .SH Name -.PP -dc - arbitrary-precision decimal reverse-Polish notation calculator +dc \- arbitrary\-precision decimal reverse\-Polish notation calculator .SH SYNOPSIS -.PP -\f[B]dc\f[R] [\f[B]-hiPRvVx\f[R]] [\f[B]--version\f[R]] -[\f[B]--help\f[R]] [\f[B]--interactive\f[R]] [\f[B]--no-prompt\f[R]] -[\f[B]--no-read-prompt\f[R]] [\f[B]--extended-register\f[R]] -[\f[B]-e\f[R] \f[I]expr\f[R]] -[\f[B]--expression\f[R]=\f[I]expr\f[R]\&...] [\f[B]-f\f[R] -\f[I]file\f[R]\&...] [\f[B]--file\f[R]=\f[I]file\f[R]\&...] +\f[B]dc\f[R] [\f[B]\-cChiPRvVx\f[R]] [\f[B]\-\-version\f[R]] +[\f[B]\-\-help\f[R]] [\f[B]\-\-digit\-clamp\f[R]] +[\f[B]\-\-no\-digit\-clamp\f[R]] [\f[B]\-\-interactive\f[R]] +[\f[B]\-\-no\-prompt\f[R]] [\f[B]\-\-no\-read\-prompt\f[R]] +[\f[B]\-\-extended\-register\f[R]] [\f[B]\-e\f[R] \f[I]expr\f[R]] +[\f[B]\-\-expression\f[R]=\f[I]expr\f[R]\&...] +[\f[B]\-f\f[R] \f[I]file\f[R]\&...] +[\f[B]\-\-file\f[R]=\f[I]file\f[R]\&...] [\f[I]file\f[R]\&...] .SH DESCRIPTION -.PP -dc(1) is an arbitrary-precision calculator. +dc(1) is an arbitrary\-precision calculator. It uses a stack (reverse Polish notation) to store numbers and results of computations. Arithmetic operations pop arguments off of the stack and push the results. .PP -If no files are given on the command-line, then dc(1) reads from +If no files are given on the command\-line, then dc(1) reads from \f[B]stdin\f[R] (see the \f[B]STDIN\f[R] section). Otherwise, those files are processed, and dc(1) will then exit. .PP If a user wants to set up a standard environment, they can use \f[B]DC_ENV_ARGS\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). For example, if a user wants the \f[B]scale\f[R] always set to -\f[B]10\f[R], they can set \f[B]DC_ENV_ARGS\f[R] to \f[B]-e 10k\f[R], +\f[B]10\f[R], they can set \f[B]DC_ENV_ARGS\f[R] to \f[B]\-e 10k\f[R], and this dc(1) will always start with a \f[B]scale\f[R] of \f[B]10\f[R]. .SH OPTIONS -.PP The following are the options that dc(1) accepts. .TP -\f[B]-h\f[R], \f[B]--help\f[R] -Prints a usage message and quits. -.TP -\f[B]-v\f[R], \f[B]-V\f[R], \f[B]--version\f[R] -Print the version information (copyright header) and exit. -.TP -\f[B]-i\f[R], \f[B]--interactive\f[R] -Forces interactive mode. -(See the \f[B]INTERACTIVE MODE\f[R] section.) +\f[B]\-C\f[R], \f[B]\-\-no\-digit\-clamp\f[R] +Disables clamping of digits greater than or equal to the current +\f[B]ibase\f[R] when parsing numbers. .RS .PP -This is a \f[B]non-portable extension\f[R]. -.RE -.TP -\f[B]-L\f[R], \f[B]--no-line-length\f[R] -Disables line length checking and prints numbers without backslashes and -newlines. -In other words, this option sets \f[B]BC_LINE_LENGTH\f[R] to \f[B]0\f[R] -(see the \f[B]ENVIRONMENT VARIABLES\f[R] section). -.RS +This means that the value added to a number from a digit is always that +digit\[cq]s value multiplied by the value of ibase raised to the power +of the digit\[cq]s position, which starts from 0 at the least +significant digit. .PP -This is a \f[B]non-portable extension\f[R]. -.RE -.TP -\f[B]-P\f[R], \f[B]--no-prompt\f[R] -Disables the prompt in TTY mode. -(The prompt is only enabled in TTY mode. -See the \f[B]TTY MODE\f[R] section.) This is mostly for those users that -do not want a prompt or are not used to having them in dc(1). -Most of those users would want to put this option in -\f[B]DC_ENV_ARGS\f[R]. -.RS +If this and/or the \f[B]\-c\f[R] or \f[B]\-\-digit\-clamp\f[R] options +are given multiple times, the last one given is used. .PP -These options override the \f[B]DC_PROMPT\f[R] and \f[B]DC_TTY_MODE\f[R] -environment variables (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +This option overrides the \f[B]DC_DIGIT_CLAMP\f[R] environment variable +(see the \f[B]ENVIRONMENT VARIABLES\f[R] section) and the default, which +can be queried with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP -\f[B]-R\f[R], \f[B]--no-read-prompt\f[R] -Disables the read prompt in TTY mode. -(The read prompt is only enabled in TTY mode. -See the \f[B]TTY MODE\f[R] section.) This is mostly for those users that -do not want a read prompt or are not used to having them in dc(1). -Most of those users would want to put this option in -\f[B]BC_ENV_ARGS\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). -This option is also useful in hash bang lines of dc(1) scripts that -prompt for user input. +\f[B]\-c\f[R], \f[B]\-\-digit\-clamp\f[R] +Enables clamping of digits greater than or equal to the current +\f[B]ibase\f[R] when parsing numbers. .RS .PP -This option does not disable the regular prompt because the read prompt -is only used when the \f[B]?\f[R] command is used. -.PP -These options \f[I]do\f[R] override the \f[B]DC_PROMPT\f[R] and -\f[B]DC_TTY_MODE\f[R] environment variables (see the \f[B]ENVIRONMENT -VARIABLES\f[R] section), but only for the read prompt. -.PP -This is a \f[B]non-portable extension\f[R]. -.RE -.TP -\f[B]-x\f[R] \f[B]--extended-register\f[R] -Enables extended register mode. -See the \f[I]Extended Register Mode\f[R] subsection of the -\f[B]REGISTERS\f[R] section for more information. -.RS +This means that digits that the value added to a number from a digit +that is greater than or equal to the ibase is the value of ibase minus 1 +all multiplied by the value of ibase raised to the power of the +digit\[cq]s position, which starts from 0 at the least significant +digit. .PP -This is a \f[B]non-portable extension\f[R]. -.RE -.TP -\f[B]-z\f[R], \f[B]--leading-zeroes\f[R] -Makes dc(1) print all numbers greater than \f[B]-1\f[R] and less than -\f[B]1\f[R], and not equal to \f[B]0\f[R], with a leading zero. -.RS +If this and/or the \f[B]\-C\f[R] or \f[B]\-\-no\-digit\-clamp\f[R] +options are given multiple times, the last one given is used. .PP -This can be set for individual numbers with the \f[B]plz(x)\f[R], -plznl(x)**, \f[B]pnlz(x)\f[R], and \f[B]pnlznl(x)\f[R] functions in the -extended math library (see the \f[B]LIBRARY\f[R] section). +This option overrides the \f[B]DC_DIGIT_CLAMP\f[R] environment variable +(see the \f[B]ENVIRONMENT VARIABLES\f[R] section) and the default, which +can be queried with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP -\f[B]-e\f[R] \f[I]expr\f[R], \f[B]--expression\f[R]=\f[I]expr\f[R] +\f[B]\-e\f[R] \f[I]expr\f[R], \f[B]\-\-expression\f[R]=\f[I]expr\f[R] Evaluates \f[I]expr\f[R]. If multiple expressions are given, they are evaluated in order. If files are given as well (see below), the expressions and files are @@ -151,41 +109,44 @@ This means that if a file is given before an expression, the file is read in and evaluated first. .RS .PP -If this option is given on the command-line (i.e., not in +If this option is given on the command\-line (i.e., not in \f[B]DC_ENV_ARGS\f[R], see the \f[B]ENVIRONMENT VARIABLES\f[R] section), then after processing all expressions and files, dc(1) will exit, unless -\f[B]-\f[R] (\f[B]stdin\f[R]) was given as an argument at least once to -\f[B]-f\f[R] or \f[B]--file\f[R], whether on the command-line or in +\f[B]\-\f[R] (\f[B]stdin\f[R]) was given as an argument at least once to +\f[B]\-f\f[R] or \f[B]\-\-file\f[R], whether on the command\-line or in \f[B]DC_ENV_ARGS\f[R]. -However, if any other \f[B]-e\f[R], \f[B]--expression\f[R], -\f[B]-f\f[R], or \f[B]--file\f[R] arguments are given after -\f[B]-f-\f[R] or equivalent is given, dc(1) will give a fatal error and -exit. +However, if any other \f[B]\-e\f[R], \f[B]\-\-expression\f[R], +\f[B]\-f\f[R], or \f[B]\-\-file\f[R] arguments are given after +\f[B]\-f\-\f[R] or equivalent is given, dc(1) will give a fatal error +and exit. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP -\f[B]-f\f[R] \f[I]file\f[R], \f[B]--file\f[R]=\f[I]file\f[R] +\f[B]\-f\f[R] \f[I]file\f[R], \f[B]\-\-file\f[R]=\f[I]file\f[R] Reads in \f[I]file\f[R] and evaluates it, line by line, as though it were read through \f[B]stdin\f[R]. If expressions are also given (see above), the expressions are evaluated in the order given. .RS .PP -If this option is given on the command-line (i.e., not in +If this option is given on the command\-line (i.e., not in \f[B]DC_ENV_ARGS\f[R], see the \f[B]ENVIRONMENT VARIABLES\f[R] section), then after processing all expressions and files, dc(1) will exit, unless -\f[B]-\f[R] (\f[B]stdin\f[R]) was given as an argument at least once to -\f[B]-f\f[R] or \f[B]--file\f[R]. -However, if any other \f[B]-e\f[R], \f[B]--expression\f[R], -\f[B]-f\f[R], or \f[B]--file\f[R] arguments are given after -\f[B]-f-\f[R] or equivalent is given, dc(1) will give a fatal error and -exit. +\f[B]\-\f[R] (\f[B]stdin\f[R]) was given as an argument at least once to +\f[B]\-f\f[R] or \f[B]\-\-file\f[R]. +However, if any other \f[B]\-e\f[R], \f[B]\-\-expression\f[R], +\f[B]\-f\f[R], or \f[B]\-\-file\f[R] arguments are given after +\f[B]\-f\-\f[R] or equivalent is given, dc(1) will give a fatal error +and exit. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP -\f[B]-I\f[R] \f[I]ibase\f[R], \f[B]--ibase\f[R]=\f[I]ibase\f[R] +\f[B]\-h\f[R], \f[B]\-\-help\f[R] +Prints a usage message and exits. +.TP +\f[B]\-I\f[R] \f[I]ibase\f[R], \f[B]\-\-ibase\f[R]=\f[I]ibase\f[R] Sets the builtin variable \f[B]ibase\f[R] to the value \f[I]ibase\f[R] assuming that \f[I]ibase\f[R] is in base 10. It is a fatal error if \f[I]ibase\f[R] is not a valid number. @@ -193,10 +154,28 @@ It is a fatal error if \f[I]ibase\f[R] is not a valid number. .PP If multiple instances of this option are given, the last is used. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP -\f[B]-O\f[R] \f[I]obase\f[R], \f[B]--obase\f[R]=\f[I]obase\f[R] +\f[B]\-i\f[R], \f[B]\-\-interactive\f[R] +Forces interactive mode. +(See the \f[B]INTERACTIVE MODE\f[R] section.) +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-L\f[R], \f[B]\-\-no\-line\-length\f[R] +Disables line length checking and prints numbers without backslashes and +newlines. +In other words, this option sets \f[B]BC_LINE_LENGTH\f[R] to \f[B]0\f[R] +(see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-O\f[R] \f[I]obase\f[R], \f[B]\-\-obase\f[R]=\f[I]obase\f[R] Sets the builtin variable \f[B]obase\f[R] to the value \f[I]obase\f[R] assuming that \f[I]obase\f[R] is in base 10. It is a fatal error if \f[I]obase\f[R] is not a valid number. @@ -204,10 +183,48 @@ It is a fatal error if \f[I]obase\f[R] is not a valid number. .PP If multiple instances of this option are given, the last is used. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-P\f[R], \f[B]\-\-no\-prompt\f[R] +Disables the prompt in TTY mode. +(The prompt is only enabled in TTY mode. +See the \f[B]TTY MODE\f[R] section.) +This is mostly for those users that do not want a prompt or are not used +to having them in dc(1). +Most of those users would want to put this option in +\f[B]DC_ENV_ARGS\f[R]. +.RS +.PP +These options override the \f[B]DC_PROMPT\f[R] and \f[B]DC_TTY_MODE\f[R] +environment variables (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-R\f[R], \f[B]\-\-no\-read\-prompt\f[R] +Disables the read prompt in TTY mode. +(The read prompt is only enabled in TTY mode. +See the \f[B]TTY MODE\f[R] section.) +This is mostly for those users that do not want a read prompt or are not +used to having them in dc(1). +Most of those users would want to put this option in +\f[B]BC_ENV_ARGS\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +This option is also useful in hash bang lines of dc(1) scripts that +prompt for user input. +.RS +.PP +This option does not disable the regular prompt because the read prompt +is only used when the \f[B]?\f[R] command is used. +.PP +These options \f[I]do\f[R] override the \f[B]DC_PROMPT\f[R] and +\f[B]DC_TTY_MODE\f[R] environment variables (see the \f[B]ENVIRONMENT +VARIABLES\f[R] section), but only for the read prompt. +.PP +This is a \f[B]non\-portable extension\f[R]. .RE .TP -\f[B]-S\f[R] \f[I]scale\f[R], \f[B]--scale\f[R]=\f[I]scale\f[R] +\f[B]\-S\f[R] \f[I]scale\f[R], \f[B]\-\-scale\f[R]=\f[I]scale\f[R] Sets the builtin variable \f[B]scale\f[R] to the value \f[I]scale\f[R] assuming that \f[I]scale\f[R] is in base 10. It is a fatal error if \f[I]scale\f[R] is not a valid number. @@ -215,15 +232,34 @@ It is a fatal error if \f[I]scale\f[R] is not a valid number. .PP If multiple instances of this option are given, the last is used. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE +.TP +\f[B]\-v\f[R], \f[B]\-V\f[R], \f[B]\-\-version\f[R] +Print the version information (copyright header) and exits. +.TP +\f[B]\-x\f[R] \f[B]\-\-extended\-register\f[R] +Enables extended register mode. +See the \f[I]Extended Register Mode\f[R] subsection of the +\f[B]REGISTERS\f[R] section for more information. +.RS .PP -All long options are \f[B]non-portable extensions\f[R]. -.SH STDIN +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-z\f[R], \f[B]\-\-leading\-zeroes\f[R] +Makes dc(1) print all numbers greater than \f[B]\-1\f[R] and less than +\f[B]1\f[R], and not equal to \f[B]0\f[R], with a leading zero. +.RS .PP -If no files are given on the command-line and no files or expressions -are given by the \f[B]-f\f[R], \f[B]--file\f[R], \f[B]-e\f[R], or -\f[B]--expression\f[R] options, then dc(1) reads from \f[B]stdin\f[R]. +This is a \f[B]non\-portable extension\f[R]. +.RE +.PP +All long options are \f[B]non\-portable extensions\f[R]. +.SH STDIN +If no files are given on the command\-line and no files or expressions +are given by the \f[B]\-f\f[R], \f[B]\-\-file\f[R], \f[B]\-e\f[R], or +\f[B]\-\-expression\f[R] options, then dc(1) reads from \f[B]stdin\f[R]. .PP However, there is a caveat to this. .PP @@ -233,8 +269,7 @@ ended. This means that, except for escaped brackets, all brackets must be balanced before dc(1) parses and executes. .SH STDOUT -.PP -Any non-error output is written to \f[B]stdout\f[R]. +Any non\-error output is written to \f[B]stdout\f[R]. In addition, if history (see the \f[B]HISTORY\f[R] section) and the prompt (see the \f[B]TTY MODE\f[R] section) are enabled, both are output to \f[B]stdout\f[R]. @@ -242,7 +277,7 @@ to \f[B]stdout\f[R]. \f[B]Note\f[R]: Unlike other dc(1) implementations, this dc(1) will issue a fatal error (see the \f[B]EXIT STATUS\f[R] section) if it cannot write to \f[B]stdout\f[R], so if \f[B]stdout\f[R] is closed, as in -\f[B]dc >&-\f[R], it will quit with an error. +\f[B]dc >&\-\f[R], it will quit with an error. This is done so that dc(1) can report problems when \f[B]stdout\f[R] is redirected to a file. .PP @@ -250,13 +285,12 @@ If there are scripts that depend on the behavior of other dc(1) implementations, it is recommended that those scripts be changed to redirect \f[B]stdout\f[R] to \f[B]/dev/null\f[R]. .SH STDERR -.PP Any error output is written to \f[B]stderr\f[R]. .PP \f[B]Note\f[R]: Unlike other dc(1) implementations, this dc(1) will issue a fatal error (see the \f[B]EXIT STATUS\f[R] section) if it cannot write to \f[B]stderr\f[R], so if \f[B]stderr\f[R] is closed, as in -\f[B]dc 2>&-\f[R], it will quit with an error. +\f[B]dc 2>&\-\f[R], it will quit with an error. This is done so that dc(1) can exit with an error code when \f[B]stderr\f[R] is redirected to a file. .PP @@ -264,7 +298,6 @@ If there are scripts that depend on the behavior of other dc(1) implementations, it is recommended that those scripts be changed to redirect \f[B]stderr\f[R] to \f[B]/dev/null\f[R]. .SH SYNTAX -.PP Each item in the input source code, either a number (see the \f[B]NUMBERS\f[R] section) or a command (see the \f[B]COMMANDS\f[R] section), is processed and executed, in order. @@ -299,30 +332,57 @@ precision of any operations (with exceptions). The max allowable value for \f[B]scale\f[R] can be queried in dc(1) programs with the \f[B]V\f[R] command. .SS Comments -.PP Comments go from \f[B]#\f[R] until, and not including, the next newline. -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .SH NUMBERS -.PP Numbers are strings made up of digits, uppercase letters up to \f[B]F\f[R], and at most \f[B]1\f[R] period for a radix. Numbers can have up to \f[B]DC_NUM_MAX\f[R] digits. -Uppercase letters are equal to \f[B]9\f[R] + their position in the +Uppercase letters are equal to \f[B]9\f[R] plus their position in the alphabet (i.e., \f[B]A\f[R] equals \f[B]10\f[R], or \f[B]9+1\f[R]). -If a digit or letter makes no sense with the current value of -\f[B]ibase\f[R], they are set to the value of the highest valid digit in -\f[B]ibase\f[R]. .PP -Single-character numbers (i.e., \f[B]A\f[R] alone) take the value that -they would have if they were valid digits, regardless of the value of -\f[B]ibase\f[R]. +If a digit or letter makes no sense with the current value of +\f[B]ibase\f[R] (i.e., they are greater than or equal to the current +value of \f[B]ibase\f[R]), then the behavior depends on the existence of +the \f[B]\-c\f[R]/\f[B]\-\-digit\-clamp\f[R] or +\f[B]\-C\f[R]/\f[B]\-\-no\-digit\-clamp\f[R] options (see the +\f[B]OPTIONS\f[R] section), the existence and setting of the +\f[B]DC_DIGIT_CLAMP\f[R] environment variable (see the \f[B]ENVIRONMENT +VARIABLES\f[R] section), or the default, which can be queried with the +\f[B]\-h\f[R]/\f[B]\-\-help\f[R] option. +.PP +If clamping is off, then digits or letters that are greater than or +equal to the current value of \f[B]ibase\f[R] are not changed. +Instead, their given value is multiplied by the appropriate power of +\f[B]ibase\f[R] and added into the number. +This means that, with an \f[B]ibase\f[R] of \f[B]3\f[R], the number +\f[B]AB\f[R] is equal to \f[B]3\[ha]1*A+3\[ha]0*B\f[R], which is +\f[B]3\f[R] times \f[B]10\f[R] plus \f[B]11\f[R], or \f[B]41\f[R]. +.PP +If clamping is on, then digits or letters that are greater than or equal +to the current value of \f[B]ibase\f[R] are set to the value of the +highest valid digit in \f[B]ibase\f[R] before being multiplied by the +appropriate power of \f[B]ibase\f[R] and added into the number. +This means that, with an \f[B]ibase\f[R] of \f[B]3\f[R], the number +\f[B]AB\f[R] is equal to \f[B]3\[ha]1*2+3\[ha]0*2\f[R], which is +\f[B]3\f[R] times \f[B]2\f[R] plus \f[B]2\f[R], or \f[B]8\f[R]. +.PP +There is one exception to clamping: single\-character numbers (i.e., +\f[B]A\f[R] alone). +Such numbers are never clamped and always take the value they would have +in the highest possible \f[B]ibase\f[R]. This means that \f[B]A\f[R] alone always equals decimal \f[B]10\f[R] and -\f[B]F\f[R] alone always equals decimal \f[B]15\f[R]. +\f[B]Z\f[R] alone always equals decimal \f[B]35\f[R]. +This behavior is mandated by the standard for bc(1) (see the STANDARDS +section) and is meant to provide an easy way to set the current +\f[B]ibase\f[R] (with the \f[B]i\f[R] command) regardless of the current +value of \f[B]ibase\f[R]. +.PP +If clamping is on, and the clamped value of a character is needed, use a +leading zero, i.e., for \f[B]A\f[R], use \f[B]0A\f[R]. .SH COMMANDS -.PP The valid commands are listed below. .SS Printing -.PP These commands are used for printing. .TP \f[B]p\f[R] @@ -343,12 +403,12 @@ Pops a value off the stack. .PP If the value is a number, it is truncated and the absolute value of the result is printed as though \f[B]obase\f[R] is \f[B]256\f[R] and each -digit is interpreted as an 8-bit ASCII character, making it a byte +digit is interpreted as an 8\-bit ASCII character, making it a byte stream. .PP If the value is a string, it is printed without a trailing newline. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]f\f[R] @@ -359,7 +419,6 @@ without altering anything. Users should use this command when they get lost. .RE .SS Arithmetic -.PP These are the commands used for arithmetic. .TP \f[B]+\f[R] @@ -368,7 +427,7 @@ pushed onto the stack. The \f[I]scale\f[R] of the result is equal to the max \f[I]scale\f[R] of both operands. .TP -\f[B]-\f[R] +\f[B]\-\f[R] The top two values are popped off the stack, subtracted, and the result is pushed onto the stack. The \f[I]scale\f[R] of the result is equal to the max \f[I]scale\f[R] of @@ -389,7 +448,7 @@ pushed onto the stack. The \f[I]scale\f[R] of the result is equal to \f[B]scale\f[R]. .RS .PP -The first value popped off of the stack must be non-zero. +The first value popped off of the stack must be non\-zero. .RE .TP \f[B]%\f[R] @@ -399,10 +458,10 @@ is pushed onto the stack. .PP Remaindering is equivalent to 1) Computing \f[B]a/b\f[R] to current \f[B]scale\f[R], and 2) Using the result of step 1 to calculate -\f[B]a-(a/b)*b\f[R] to \f[I]scale\f[R] +\f[B]a\-(a/b)*b\f[R] to \f[I]scale\f[R] \f[B]max(scale+scale(b),scale(a))\f[R]. .PP -The first value popped off of the stack must be non-zero. +The first value popped off of the stack must be non\-zero. .RE .TP \f[B]\[ti]\f[R] @@ -413,9 +472,9 @@ This is equivalent to \f[B]x y / x y %\f[R] except that \f[B]x\f[R] and \f[B]y\f[R] are only evaluated once. .RS .PP -The first value popped off of the stack must be non-zero. +The first value popped off of the stack must be non\-zero. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]\[ha]\f[R] @@ -426,7 +485,7 @@ The \f[I]scale\f[R] of the result is equal to \f[B]scale\f[R]. .PP The first value popped off of the stack must be an integer, and if that value is negative, the second value popped off of the stack must be -non-zero. +non\-zero. .RE .TP \f[B]v\f[R] @@ -435,7 +494,7 @@ the result is pushed onto the stack. The \f[I]scale\f[R] of the result is equal to \f[B]scale\f[R]. .RS .PP -The value popped off of the stack must be non-negative. +The value popped off of the stack must be non\-negative. .RE .TP \f[B]_\f[R] @@ -445,7 +504,7 @@ or other commands), then that number is input as a negative number. .PP Otherwise, the top value on the stack is popped and copied, and the copy is negated and pushed onto the stack. -This behavior without a number is a \f[B]non-portable extension\f[R]. +This behavior without a number is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]b\f[R] @@ -454,7 +513,7 @@ back onto the stack. Otherwise, its absolute value is pushed onto the stack. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]|\f[R] @@ -463,12 +522,12 @@ is computed, and the result is pushed onto the stack. .RS .PP The first value popped is used as the reduction modulus and must be an -integer and non-zero. +integer and non\-zero. The second value popped is used as the exponent and must be an integer -and non-negative. +and non\-negative. The third value popped is the base and must be an integer. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]G\f[R] @@ -476,7 +535,7 @@ The top two values are popped off of the stack, they are compared, and a \f[B]1\f[R] is pushed if they are equal, or \f[B]0\f[R] otherwise. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]N\f[R] @@ -484,7 +543,7 @@ The top value is popped off of the stack, and if it a \f[B]0\f[R], a \f[B]1\f[R] is pushed; otherwise, a \f[B]0\f[R] is pushed. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B](\f[R] @@ -493,7 +552,7 @@ The top two values are popped off of the stack, they are compared, and a \f[B]0\f[R] otherwise. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]{\f[R] @@ -502,7 +561,7 @@ The top two values are popped off of the stack, they are compared, and a or \f[B]0\f[R] otherwise. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B])\f[R] @@ -511,7 +570,7 @@ The top two values are popped off of the stack, they are compared, and a \f[B]0\f[R] otherwise. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]}\f[R] @@ -520,36 +579,35 @@ The top two values are popped off of the stack, they are compared, and a second, or \f[B]0\f[R] otherwise. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]M\f[R] The top two values are popped off of the stack. -If they are both non-zero, a \f[B]1\f[R] is pushed onto the stack. +If they are both non\-zero, a \f[B]1\f[R] is pushed onto the stack. If either of them is zero, or both of them are, then a \f[B]0\f[R] is pushed onto the stack. .RS .PP This is like the \f[B]&&\f[R] operator in bc(1), and it is \f[I]not\f[R] -a short-circuit operator. +a short\-circuit operator. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]m\f[R] The top two values are popped off of the stack. -If at least one of them is non-zero, a \f[B]1\f[R] is pushed onto the +If at least one of them is non\-zero, a \f[B]1\f[R] is pushed onto the stack. If both of them are zero, then a \f[B]0\f[R] is pushed onto the stack. .RS .PP This is like the \f[B]||\f[R] operator in bc(1), and it is \f[I]not\f[R] -a short-circuit operator. +a short\-circuit operator. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .SS Stack Control -.PP These commands control the stack. .TP \f[B]c\f[R] @@ -565,7 +623,6 @@ Swaps (\[lq]reverses\[rq]) the two top items on the stack. \f[B]R\f[R] Pops (\[lq]removes\[rq]) the top value from the stack. .SS Register Control -.PP These commands control registers (see the \f[B]REGISTERS\f[R] section). .TP \f[B]s\f[R]\f[I]r\f[R] @@ -587,7 +644,6 @@ push it onto the main stack. The previous value in the stack for register \f[I]r\f[R], if any, is now accessible via the \f[B]l\f[R]\f[I]r\f[R] command. .SS Parameters -.PP These commands control the values of \f[B]ibase\f[R], \f[B]obase\f[R], and \f[B]scale\f[R]. Also see the \f[B]SYNTAX\f[R] section. @@ -614,7 +670,7 @@ If the value on top of the stack has any \f[I]scale\f[R], the .TP \f[B]k\f[R] Pops the value off of the top of the stack and uses it to set -\f[B]scale\f[R], which must be non-negative. +\f[B]scale\f[R], which must be non\-negative. .RS .PP If the value on top of the stack has any \f[I]scale\f[R], the @@ -635,7 +691,7 @@ Pushes the maximum allowable value of \f[B]ibase\f[R] onto the main stack. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]U\f[R] @@ -643,7 +699,7 @@ Pushes the maximum allowable value of \f[B]obase\f[R] onto the main stack. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]V\f[R] @@ -651,10 +707,9 @@ Pushes the maximum allowable value of \f[B]scale\f[R] onto the main stack. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .SS Strings -.PP The following commands control strings. .PP dc(1) can work with both numbers and strings, and registers (see the @@ -692,16 +747,16 @@ The value on top of the stack is popped. If it is a number, it is truncated and its absolute value is taken. The result mod \f[B]256\f[R] is calculated. If that result is \f[B]0\f[R], push an empty string; otherwise, push a -one-character string where the character is the result of the mod +one\-character string where the character is the result of the mod interpreted as an ASCII character. .PP If it is a string, then a new string is made. If the original string is empty, the new string is empty. If it is not, then the first character of the original string is used to -create the new string as a one-character string. +create the new string as a one\-character string. The new string is then pushed onto the stack. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]x\f[R] @@ -737,7 +792,7 @@ fails. If either or both of the values are not numbers, dc(1) will raise an error and reset (see the \f[B]RESET\f[R] section). .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]!>\f[R]\f[I]r\f[R] @@ -758,7 +813,7 @@ fails. If either or both of the values are not numbers, dc(1) will raise an error and reset (see the \f[B]RESET\f[R] section). .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]<\f[R]\f[I]r\f[R] @@ -779,7 +834,7 @@ fails. If either or both of the values are not numbers, dc(1) will raise an error and reset (see the \f[B]RESET\f[R] section). .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]!<\f[R]\f[I]r\f[R] @@ -800,7 +855,7 @@ fails. If either or both of the values are not numbers, dc(1) will raise an error and reset (see the \f[B]RESET\f[R] section). .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]=\f[R]\f[I]r\f[R] @@ -821,7 +876,7 @@ fails. If either or both of the values are not numbers, dc(1) will raise an error and reset (see the \f[B]RESET\f[R] section). .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]!=\f[R]\f[I]r\f[R] @@ -842,7 +897,7 @@ fails. If either or both of the values are not numbers, dc(1) will raise an error and reset (see the \f[B]RESET\f[R] section). .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .TP \f[B]?\f[R] @@ -855,7 +910,7 @@ the execution of the macro that executed it. If there are no macros, or only one macro executing, dc(1) exits. .TP \f[B]Q\f[R] -Pops a value from the stack which must be non-negative and is used the +Pops a value from the stack which must be non\-negative and is used the number of macro executions to pop off of the execution stack. If the number of levels to pop is greater than the number of executing macros, dc(1) exits. @@ -866,8 +921,11 @@ The execution stack is the stack of string executions. The number that is pushed onto the stack is exactly as many as is needed to make dc(1) exit with the \f[B]Q\f[R] command, so the sequence \f[B],Q\f[R] will make dc(1) exit. -.SS Status +.RS .PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.SS Status These commands query status of the stack or its top value. .TP \f[B]Z\f[R] @@ -892,6 +950,24 @@ stack. If it is a string, pushes \f[B]0\f[R]. .RE .TP +\f[B]u\f[R] +Pops one value off of the stack. +If the value is a number, this pushes \f[B]1\f[R] onto the stack. +Otherwise (if it is a string), it pushes \f[B]0\f[R]. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]t\f[R] +Pops one value off of the stack. +If the value is a string, this pushes \f[B]1\f[R] onto the stack. +Otherwise (if it is a number), it pushes \f[B]0\f[R]. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP \f[B]z\f[R] Pushes the current depth of the stack (before execution of this command) onto the stack. @@ -907,10 +983,9 @@ register\[cq]s stack must always have at least one item; dc(1) will give an error and reset otherwise (see the \f[B]RESET\f[R] section). This means that this command will never push \f[B]0\f[R]. .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .SS Arrays -.PP These commands manipulate arrays. .TP \f[B]:\f[R]\f[I]r\f[R] @@ -927,10 +1002,9 @@ The selected value is then pushed onto the stack. Pushes the length of the array \f[I]r\f[R] onto the stack. .RS .PP -This is a \f[B]non-portable extension\f[R]. +This is a \f[B]non\-portable extension\f[R]. .RE .SS Global Settings -.PP These commands retrieve global settings. These are the only commands that require multiple specific characters, and all of them begin with the letter \f[B]g\f[R]. @@ -942,12 +1016,17 @@ section). Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack. .TP +\f[B]gx\f[R] +Pushes \f[B]1\f[R] onto the stack if extended register mode is on, +\f[B]0\f[R] otherwise. +See the \f[I]Extended Register Mode\f[R] subsection of the +\f[B]REGISTERS\f[R] section for more information. +.TP \f[B]gz\f[R] Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not -been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options -(see the \f[B]OPTIONS\f[R] section), non-zero otherwise. +been enabled with the \f[B]\-z\f[R] or \f[B]\-\-leading\-zeroes\f[R] +options (see the \f[B]OPTIONS\f[R] section), non\-zero otherwise. .SH REGISTERS -.PP Registers are names that can store strings, numbers, and arrays. (Number/string registers do not interfere with array registers.) .PP @@ -957,45 +1036,45 @@ All registers, when first referenced, have one value (\f[B]0\f[R]) in their stack, and it is a runtime error to attempt to pop that item off of the register stack. .PP -In non-extended register mode, a register name is just the single +In non\-extended register mode, a register name is just the single character that follows any command that needs a register name. The only exceptions are: a newline (\f[B]`\[rs]n'\f[R]) and a left bracket (\f[B]`['\f[R]); it is a parse error for a newline or a left bracket to be used as a register name. .SS Extended Register Mode -.PP Unlike most other dc(1) implentations, this dc(1) provides nearly unlimited amounts of registers, if extended register mode is enabled. .PP -If extended register mode is enabled (\f[B]-x\f[R] or -\f[B]--extended-register\f[R] command-line arguments are given), then -normal single character registers are used \f[I]unless\f[R] the +If extended register mode is enabled (\f[B]\-x\f[R] or +\f[B]\-\-extended\-register\f[R] command\-line arguments are given), +then normal single character registers are used \f[I]unless\f[R] the character immediately following a command that needs a register name is a space (according to \f[B]isspace()\f[R]) and not a newline (\f[B]`\[rs]n'\f[R]). .PP In that case, the register name is found according to the regex -\f[B][a-z][a-z0-9_]*\f[R] (like bc(1) identifiers), and it is a parse -error if the next non-space characters do not match that regex. +\f[B][a\-z][a\-z0\-9_]*\f[R] (like bc(1) identifiers), and it is a parse +error if the next non\-space characters do not match that regex. .SH RESET -.PP -When dc(1) encounters an error or a signal that it has a non-default +When dc(1) encounters an error or a signal that it has a non\-default handler for, it resets. This means that several things happen. .PP First, any macros that are executing are stopped and popped off the -stack. +execution stack. The behavior is not unlike that of exceptions in programming languages. Then the execution point is set so that any code waiting to execute (after all macros returned) is skipped. .PP +However, the stack of values is \f[I]not\f[R] cleared; in interactive +mode, users can inspect the stack and manipulate it. +.PP Thus, when dc(1) resets, it skips any remaining code waiting to be executed. Then, if it is interactive mode, and the error was not a fatal error (see the \f[B]EXIT STATUS\f[R] section), it asks for more input; otherwise, it exits with the appropriate return code. .SH PERFORMANCE -.PP Most dc(1) implementations use \f[B]char\f[R] types to calculate the value of \f[B]1\f[R] decimal digit at a time, but that can be slow. This dc(1) does something different. @@ -1015,7 +1094,6 @@ checking. This integer type depends on the value of \f[B]DC_LONG_BIT\f[R], but is always at least twice as large as the integer type used to store digits. .SH LIMITS -.PP The following are the limits on dc(1): .TP \f[B]DC_LONG_BIT\f[R] @@ -1045,24 +1123,24 @@ Set at \f[B]DC_BASE_POW\f[R]. .TP \f[B]DC_DIM_MAX\f[R] The maximum size of arrays. -Set at \f[B]SIZE_MAX-1\f[R]. +Set at \f[B]SIZE_MAX\-1\f[R]. .TP \f[B]DC_SCALE_MAX\f[R] The maximum \f[B]scale\f[R]. -Set at \f[B]DC_OVERFLOW_MAX-1\f[R]. +Set at \f[B]DC_OVERFLOW_MAX\-1\f[R]. .TP \f[B]DC_STRING_MAX\f[R] The maximum length of strings. -Set at \f[B]DC_OVERFLOW_MAX-1\f[R]. +Set at \f[B]DC_OVERFLOW_MAX\-1\f[R]. .TP \f[B]DC_NAME_MAX\f[R] The maximum length of identifiers. -Set at \f[B]DC_OVERFLOW_MAX-1\f[R]. +Set at \f[B]DC_OVERFLOW_MAX\-1\f[R]. .TP \f[B]DC_NUM_MAX\f[R] The maximum length of a number (in decimal digits), which includes digits after the decimal point. -Set at \f[B]DC_OVERFLOW_MAX-1\f[R]. +Set at \f[B]DC_OVERFLOW_MAX\-1\f[R]. .TP Exponent The maximum allowable exponent (positive or negative). @@ -1070,27 +1148,27 @@ Set at \f[B]DC_OVERFLOW_MAX\f[R]. .TP Number of vars The maximum number of vars/arrays. -Set at \f[B]SIZE_MAX-1\f[R]. +Set at \f[B]SIZE_MAX\-1\f[R]. .PP -These limits are meant to be effectively non-existent; the limits are so -large (at least on 64-bit machines) that there should not be any point -at which they become a problem. +These limits are meant to be effectively non\-existent; the limits are +so large (at least on 64\-bit machines) that there should not be any +point at which they become a problem. In fact, memory should be exhausted before these limits should be hit. .SH ENVIRONMENT VARIABLES -.PP -dc(1) recognizes the following environment variables: +As \f[B]non\-portable extensions\f[R], dc(1) recognizes the following +environment variables: .TP \f[B]DC_ENV_ARGS\f[R] -This is another way to give command-line arguments to dc(1). -They should be in the same format as all other command-line arguments. +This is another way to give command\-line arguments to dc(1). +They should be in the same format as all other command\-line arguments. These are always processed first, so any files given in \f[B]DC_ENV_ARGS\f[R] will be processed before arguments and files given -on the command-line. +on the command\-line. This gives the user the ability to set up \[lq]standard\[rq] options and files to be used at every invocation. The most useful thing for such files to contain would be useful functions that the user might want every time dc(1) runs. -Another use would be to use the \f[B]-e\f[R] option to set +Another use would be to use the \f[B]\-e\f[R] option to set \f[B]scale\f[R] to a value other than \f[B]0\f[R]. .RS .PP @@ -1108,14 +1186,14 @@ you can use double quotes as the outside quotes, as in \f[B]\[lq]some quotes. However, handling a file with both kinds of quotes in \f[B]DC_ENV_ARGS\f[R] is not supported due to the complexity of the -parsing, though such files are still supported on the command-line where -the parsing is done by the shell. +parsing, though such files are still supported on the command\-line +where the parsing is done by the shell. .RE .TP \f[B]DC_LINE_LENGTH\f[R] If this environment variable exists and contains an integer that is greater than \f[B]1\f[R] and is less than \f[B]UINT16_MAX\f[R] -(\f[B]2\[ha]16-1\f[R]), dc(1) will output lines to that length, +(\f[B]2\[ha]16\-1\f[R]), dc(1) will output lines to that length, including the backslash newline combo. The default line length is \f[B]70\f[R]. .RS @@ -1132,13 +1210,13 @@ exits on \f[B]SIGINT\f[R] when not in interactive mode. .RS .PP However, when dc(1) is in interactive mode, then if this environment -variable exists and contains an integer, a non-zero value makes dc(1) +variable exists and contains an integer, a non\-zero value makes dc(1) reset on \f[B]SIGINT\f[R], rather than exit, and zero makes dc(1) exit. If this environment variable exists and is \f[I]not\f[R] an integer, then dc(1) will exit on \f[B]SIGINT\f[R]. .PP This environment variable overrides the default, which can be queried -with the \f[B]-h\f[R] or \f[B]--help\f[R] options. +with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. .RE .TP \f[B]DC_TTY_MODE\f[R] @@ -1147,11 +1225,11 @@ section), then this environment variable has no effect. .RS .PP However, when TTY mode is available, then if this environment variable -exists and contains an integer, then a non-zero value makes dc(1) use +exists and contains an integer, then a non\-zero value makes dc(1) use TTY mode, and zero makes dc(1) not use TTY mode. .PP This environment variable overrides the default, which can be queried -with the \f[B]-h\f[R] or \f[B]--help\f[R] options. +with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. .RE .TP \f[B]DC_PROMPT\f[R] @@ -1160,30 +1238,46 @@ section), then this environment variable has no effect. .RS .PP However, when TTY mode is available, then if this environment variable -exists and contains an integer, a non-zero value makes dc(1) use a -prompt, and zero or a non-integer makes dc(1) not use a prompt. +exists and contains an integer, a non\-zero value makes dc(1) use a +prompt, and zero or a non\-integer makes dc(1) not use a prompt. If this environment variable does not exist and \f[B]DC_TTY_MODE\f[R] does, then the value of the \f[B]DC_TTY_MODE\f[R] environment variable is used. .PP This environment variable and the \f[B]DC_TTY_MODE\f[R] environment variable override the default, which can be queried with the -\f[B]-h\f[R] or \f[B]--help\f[R] options. +\f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. .RE .TP \f[B]DC_EXPR_EXIT\f[R] -If any expressions or expression files are given on the command-line -with \f[B]-e\f[R], \f[B]--expression\f[R], \f[B]-f\f[R], or -\f[B]--file\f[R], then if this environment variable exists and contains -an integer, a non-zero value makes dc(1) exit after executing the -expressions and expression files, and a zero value makes dc(1) not exit. +If any expressions or expression files are given on the command\-line +with \f[B]\-e\f[R], \f[B]\-\-expression\f[R], \f[B]\-f\f[R], or +\f[B]\-\-file\f[R], then if this environment variable exists and +contains an integer, a non\-zero value makes dc(1) exit after executing +the expressions and expression files, and a zero value makes dc(1) not +exit. .RS .PP This environment variable overrides the default, which can be queried -with the \f[B]-h\f[R] or \f[B]--help\f[R] options. +with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. .RE -.SH EXIT STATUS +.TP +\f[B]DC_DIGIT_CLAMP\f[R] +When parsing numbers and if this environment variable exists and +contains an integer, a non\-zero value makes dc(1) clamp digits that are +greater than or equal to the current \f[B]ibase\f[R] so that all such +digits are considered equal to the \f[B]ibase\f[R] minus 1, and a zero +value disables such clamping so that those digits are always equal to +their value, which is multiplied by the power of the \f[B]ibase\f[R]. +.RS +.PP +This never applies to single\-digit numbers, as per the bc(1) standard +(see the \f[B]STANDARDS\f[R] section). .PP +This environment variable overrides the default, which can be queried +with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. +.RE +.SH EXIT STATUS dc(1) returns the following exit statuses: .TP \f[B]0\f[R] @@ -1199,7 +1293,7 @@ Math errors include divide by \f[B]0\f[R], taking the square root of a negative number, attempting to convert a negative number to a hardware integer, overflow when converting a number to a hardware integer, overflow when calculating the size of a number, and attempting to use a -non-integer where an integer is required. +non\-integer where an integer is required. .PP Converting to a hardware integer happens for the second operand of the power (\f[B]\[ha]\f[R]) operator. @@ -1233,7 +1327,7 @@ A fatal error occurred. Fatal errors include memory allocation errors, I/O errors, failing to open files, attempting to use files that do not have only ASCII characters (dc(1) only accepts ASCII characters), attempting to open a -directory as a file, and giving invalid command-line options. +directory as a file, and giving invalid command\-line options. .RE .PP The exit status \f[B]4\f[R] is special; when a fatal error occurs, dc(1) @@ -1244,17 +1338,17 @@ interactive mode (see the \f[B]INTERACTIVE MODE\f[R] section), since dc(1) resets its state (see the \f[B]RESET\f[R] section) and accepts more input when one of those errors occurs in interactive mode. This is also the case when interactive mode is forced by the -\f[B]-i\f[R] flag or \f[B]--interactive\f[R] option. +\f[B]\-i\f[R] flag or \f[B]\-\-interactive\f[R] option. .PP These exit statuses allow dc(1) to be used in shell scripting with error checking, and its normal behavior can be forced by using the -\f[B]-i\f[R] flag or \f[B]--interactive\f[R] option. +\f[B]\-i\f[R] flag or \f[B]\-\-interactive\f[R] option. .SH INTERACTIVE MODE -.PP -Like bc(1), dc(1) has an interactive mode and a non-interactive mode. +Like bc(1), dc(1) has an interactive mode and a non\-interactive mode. Interactive mode is turned on automatically when both \f[B]stdin\f[R] -and \f[B]stdout\f[R] are hooked to a terminal, but the \f[B]-i\f[R] flag -and \f[B]--interactive\f[R] option can turn it on in other situations. +and \f[B]stdout\f[R] are hooked to a terminal, but the \f[B]\-i\f[R] +flag and \f[B]\-\-interactive\f[R] option can turn it on in other +situations. .PP In interactive mode, dc(1) attempts to recover from errors (see the \f[B]RESET\f[R] section), and in normal execution, flushes @@ -1263,7 +1357,6 @@ dc(1) may also reset on \f[B]SIGINT\f[R] instead of exit, depending on the contents of, or default for, the \f[B]DC_SIGINT_RESET\f[R] environment variable (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). .SH TTY MODE -.PP If \f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are all connected to a TTY, then \[lq]TTY mode\[rq] is considered to be available, and thus, dc(1) can turn on TTY mode, subject to some @@ -1271,53 +1364,49 @@ settings. .PP If there is the environment variable \f[B]DC_TTY_MODE\f[R] in the environment (see the \f[B]ENVIRONMENT VARIABLES\f[R] section), then if -that environment variable contains a non-zero integer, dc(1) will turn +that environment variable contains a non\-zero integer, dc(1) will turn on TTY mode when \f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are all connected to a TTY. If the \f[B]DC_TTY_MODE\f[R] environment variable exists but is -\f[I]not\f[R] a non-zero integer, then dc(1) will not turn TTY mode on. +\f[I]not\f[R] a non\-zero integer, then dc(1) will not turn TTY mode on. .PP If the environment variable \f[B]DC_TTY_MODE\f[R] does \f[I]not\f[R] exist, the default setting is used. -The default setting can be queried with the \f[B]-h\f[R] or -\f[B]--help\f[R] options. +The default setting can be queried with the \f[B]\-h\f[R] or +\f[B]\-\-help\f[R] options. .PP TTY mode is different from interactive mode because interactive mode is -required in the bc(1) specification at -https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html , and -interactive mode requires only \f[B]stdin\f[R] and \f[B]stdout\f[R] to -be connected to a terminal. -.SS Command-Line History -.PP -Command-line history is only enabled if TTY mode is, i.e., that +required in the bc(1) specification (see the \f[B]STANDARDS\f[R] +section), and interactive mode requires only \f[B]stdin\f[R] and +\f[B]stdout\f[R] to be connected to a terminal. +.SS Command\-Line History +Command\-line history is only enabled if TTY mode is, i.e., that \f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are connected to a TTY and the \f[B]DC_TTY_MODE\f[R] environment variable (see the \f[B]ENVIRONMENT VARIABLES\f[R] section) and its default do not disable TTY mode. See the \f[B]COMMAND LINE HISTORY\f[R] section for more information. .SS Prompt -.PP If TTY mode is available, then a prompt can be enabled. Like TTY mode itself, it can be turned on or off with an environment variable: \f[B]DC_PROMPT\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). .PP -If the environment variable \f[B]DC_PROMPT\f[R] exists and is a non-zero -integer, then the prompt is turned on when \f[B]stdin\f[R], +If the environment variable \f[B]DC_PROMPT\f[R] exists and is a +non\-zero integer, then the prompt is turned on when \f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are connected to a TTY and the -\f[B]-P\f[R] and \f[B]--no-prompt\f[R] options were not used. +\f[B]\-P\f[R] and \f[B]\-\-no\-prompt\f[R] options were not used. The read prompt will be turned on under the same conditions, except that -the \f[B]-R\f[R] and \f[B]--no-read-prompt\f[R] options must also not be -used. +the \f[B]\-R\f[R] and \f[B]\-\-no\-read\-prompt\f[R] options must also +not be used. .PP However, if \f[B]DC_PROMPT\f[R] does not exist, the prompt can be enabled or disabled with the \f[B]DC_TTY_MODE\f[R] environment variable, -the \f[B]-P\f[R] and \f[B]--no-prompt\f[R] options, and the \f[B]-R\f[R] -and \f[B]--no-read-prompt\f[R] options. +the \f[B]\-P\f[R] and \f[B]\-\-no\-prompt\f[R] options, and the +\f[B]\-R\f[R] and \f[B]\-\-no\-read\-prompt\f[R] options. See the \f[B]ENVIRONMENT VARIABLES\f[R] and \f[B]OPTIONS\f[R] sections for more details. .SH SIGNAL HANDLING -.PP Sending a \f[B]SIGINT\f[R] will cause dc(1) to do one of two things. .PP If dc(1) is not in interactive mode (see the \f[B]INTERACTIVE MODE\f[R] @@ -1326,7 +1415,7 @@ section), or the \f[B]DC_SIGINT_RESET\f[R] environment variable (see the an integer or it is zero, dc(1) will exit. .PP However, if dc(1) is in interactive mode, and the -\f[B]DC_SIGINT_RESET\f[R] or its default is an integer and non-zero, +\f[B]DC_SIGINT_RESET\f[R] or its default is an integer and non\-zero, then dc(1) will stop executing the current input and reset (see the \f[B]RESET\f[R] section) upon receiving a \f[B]SIGINT\f[R]. .PP @@ -1352,12 +1441,11 @@ The one exception is \f[B]SIGHUP\f[R]; in that case, and only when dc(1) is in TTY mode (see the \f[B]TTY MODE\f[R] section), a \f[B]SIGHUP\f[R] will cause dc(1) to clean up and exit. .SH COMMAND LINE HISTORY -.PP -dc(1) supports interactive command-line editing. +dc(1) supports interactive command\-line editing. .PP If dc(1) can be in TTY mode (see the \f[B]TTY MODE\f[R] section), history can be enabled. -This means that command-line history can only be enabled when +This means that command\-line history can only be enabled when \f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are all connected to a TTY. .PP @@ -1367,19 +1455,17 @@ section). .PP \f[B]Note\f[R]: tabs are converted to 8 spaces. .SH SEE ALSO -.PP bc(1) .SH STANDARDS -.PP -The dc(1) utility operators are compliant with the operators in the IEEE -Std 1003.1-2017 (\[lq]POSIX.1-2017\[rq]) specification at -https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html for -bc(1). +The dc(1) utility operators and some behavior are compliant with the +operators in the IEEE Std 1003.1\-2017 (\[lq]POSIX.1\-2017\[rq]) bc(1) +specification at +https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html . .SH BUGS -.PP None are known. -Report bugs at https://git.yzena.com/gavin/bc. +Report bugs at https://github.com/gavinhoward/bc . .SH AUTHOR -.PP -Gavin D. -Howard <gavin@yzena.com> and contributors. +Gavin D. Howard \c +.MT gavin@gavinhoward.com +.ME \c +\ and contributors. |