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Diffstat (limited to 'lib/libc/gen/sysconf.3')
| -rw-r--r-- | lib/libc/gen/sysconf.3 | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/lib/libc/gen/sysconf.3 b/lib/libc/gen/sysconf.3 new file mode 100644 index 000000000000..4631aeb6bf1b --- /dev/null +++ b/lib/libc/gen/sysconf.3 @@ -0,0 +1,276 @@ +.\" Copyright (c) 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)sysconf.3 8.3 (Berkeley) 4/19/94 +.\" $FreeBSD$ +.\" +.Dd April 26, 2013 +.Dt SYSCONF 3 +.Os +.Sh NAME +.Nm sysconf +.Nd get configurable system variables +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In unistd.h +.Ft long +.Fn sysconf "int name" +.Sh DESCRIPTION +This interface is defined by +.St -p1003.1-88 . +A far more complete interface is available using +.Xr sysctl 3 . +.Pp +The +.Fn sysconf +function provides a method for applications to determine the current +value of a configurable system limit or option variable. +The +.Fa name +argument specifies the system variable to be queried. +Symbolic constants for each name value are found in the include file +.In unistd.h . +Shell programmers who need access to these parameters should use the +.Xr getconf 1 +utility. +.Pp +The available values are as follows: +.Bl -tag -width 6n +.It Li _SC_ARG_MAX +The maximum bytes of argument to +.Xr execve 2 . +.It Li _SC_CHILD_MAX +The maximum number of simultaneous processes per user id. +.It Li _SC_CLK_TCK +The frequency of the statistics clock in ticks per second. +.It Li _SC_IOV_MAX +The maximum number of elements in the I/O vector used by +.Xr readv 2 , +.Xr writev 2 , +.Xr recvmsg 2 , +and +.Xr sendmsg 2 . +.It Li _SC_NGROUPS_MAX +The maximum number of supplemental groups. +.It Li _SC_NPROCESSORS_CONF +The number of processors configured. +.It Li _SC_NPROCESSORS_ONLN +The number of processors currently online. +.It Li _SC_OPEN_MAX +One more than the maximum value the system may assign to a new file descriptor. +.It Li _SC_PAGESIZE +The size of a system page in bytes. +.It Li _SC_PAGE_SIZE +Equivalent to +.Li _SC_PAGESIZE . +.It Li _SC_STREAM_MAX +The minimum maximum number of streams that a process may have open +at any one time. +.It Li _SC_TZNAME_MAX +The minimum maximum number of types supported for the name of a +timezone. +.It Li _SC_JOB_CONTROL +Return 1 if job control is available on this system, otherwise \-1. +.It Li _SC_SAVED_IDS +Returns 1 if saved set-group and saved set-user ID is available, +otherwise \-1. +.It Li _SC_VERSION +The version of +.St -p1003.1 +with which the system +attempts to comply. +.It Li _SC_BC_BASE_MAX +The maximum ibase/obase values in the +.Xr bc 1 +utility. +.It Li _SC_BC_DIM_MAX +The maximum array size in the +.Xr bc 1 +utility. +.It Li _SC_BC_SCALE_MAX +The maximum scale value in the +.Xr bc 1 +utility. +.It Li _SC_BC_STRING_MAX +The maximum string length in the +.Xr bc 1 +utility. +.It Li _SC_COLL_WEIGHTS_MAX +The maximum number of weights that can be assigned to any entry of +the LC_COLLATE order keyword in the locale definition file. +.It Li _SC_EXPR_NEST_MAX +The maximum number of expressions that can be nested within +parenthesis by the +.Xr expr 1 +utility. +.It Li _SC_LINE_MAX +The maximum length in bytes of a text-processing utility's input +line. +.It Li _SC_RE_DUP_MAX +The maximum number of repeated occurrences of a regular expression +permitted when using interval notation. +.It Li _SC_2_VERSION +The version of +.St -p1003.2 +with which the system attempts to comply. +.It Li _SC_2_C_BIND +Return 1 if the system's C-language development facilities support the +C-Language Bindings Option, otherwise \-1. +.It Li _SC_2_C_DEV +Return 1 if the system supports the C-Language Development Utilities Option, +otherwise \-1. +.It Li _SC_2_CHAR_TERM +Return 1 if the system supports at least one terminal type capable of +all operations described in +.St -p1003.2 , +otherwise \-1. +.It Li _SC_2_FORT_DEV +Return 1 if the system supports the FORTRAN Development Utilities Option, +otherwise \-1. +.It Li _SC_2_FORT_RUN +Return 1 if the system supports the FORTRAN Runtime Utilities Option, +otherwise \-1. +.It Li _SC_2_LOCALEDEF +Return 1 if the system supports the creation of locales, otherwise \-1. +.It Li _SC_2_SW_DEV +Return 1 if the system supports the Software Development Utilities Option, +otherwise \-1. +.It Li _SC_2_UPE +Return 1 if the system supports the User Portability Utilities Option, +otherwise \-1. +.It Li _SC_AIO_LISTIO_MAX +Maximum number of I/O operations in a single list I/O call supported. +.It Li _SC_AIO_MAX +Maximum number of outstanding asynchronous I/O operations supported. +.It Li _SC_AIO_PRIO_DELTA_MAX +The maximum amount by which a process can decrease its asynchronous I/O +priority level from its own scheduling priority. +.It Li _SC_DELAYTIMER_MAX +Maximum number of timer expiration overruns. +.It Li _SC_MQ_OPEN_MAX +The maximum number of open message queue descriptors a process may hold. +.It Li _SC_RTSIG_MAX +Maximum number of realtime signals reserved for application use. +.It Li _SC_SEM_NSEMS_MAX +Maximum number of semaphores that a process may have. +.It Li _SC_SEM_VALUE_MAX +The maximum value a semaphore may have. +.It Li _SC_SIGQUEUE_MAX +Maximum number of queued signals that a process may send and have pending at +the receiver(s) at any time. +.It Li _SC_TIMER_MAX +Maximum number of timers per process supported. +.It Li _SC_GETGR_R_SIZE_MAX +Suggested initial value for the size of the group entry buffer. +.It Li _SC_GETPW_R_SIZE_MAX +Suggested initial value for the size of the password entry buffer. +.It Li _SC_HOST_NAME_MAX +Maximum length of a host name (not including the terminating null) as +returned from the +.Fn gethostname +function. +.It Li _SC_LOGIN_NAME_MAX +Maximum length of a login name. +.It Li _SC_THREAD_STACK_MIN +Minimum size in bytes of thread stack storage. +.It Li _SC_THREAD_THREADS_MAX +Maximum number of threads that can be created per process. +.It Li _SC_TTY_NAME_MAX +Maximum length of terminal device name. +.It Li _SC_SYMLOOP_MAX +Maximum number of symbolic links that can be reliably traversed in the +resolution of a pathname in the absence of a loop. +.It Li _SC_ATEXIT_MAX +Maximum number of functions that may be registered with +.Fn atexit . +.It Li _SC_XOPEN_VERSION +An integer value greater than or equal to 4, +indicating the version of the X/Open Portability Guide to which this +system conforms. +.It Li _SC_XOPEN_XCU_VERSION +An integer value indicating the version of the XCU Specification to which +this system conforms. +.El +.Pp +These values also exist, but may not be standard: +.Bl -tag -width 6n +.It Li _SC_CPUSET_SIZE +Size of the kernel cpuset. +.It Li _SC_PHYS_PAGES +The number of pages of physical memory. +Note that it is possible that the product of this value and the value of +.Li _SC_PAGESIZE +will overflow a +.Vt long +in some configurations on a 32bit machine. +.El +.Sh RETURN VALUES +If the call to +.Fn sysconf +is not successful, \-1 is returned and +.Va errno +is set appropriately. +Otherwise, if the variable is associated with functionality that is not +supported, \-1 is returned and +.Va errno +is not modified. +Otherwise, the current variable value is returned. +.Sh ERRORS +The +.Fn sysconf +function may fail and set +.Va errno +for any of the errors specified for the library function +.Xr sysctl 3 . +In addition, the following error may be reported: +.Bl -tag -width Er +.It Bq Er EINVAL +The value of the +.Fa name +argument is invalid. +.El +.Sh SEE ALSO +.Xr getconf 1 , +.Xr pathconf 2 , +.Xr confstr 3 , +.Xr sysctl 3 +.Sh STANDARDS +Except for the fact that values returned by +.Fn sysconf +may change over the lifetime of the calling process, +this function conforms to +.St -p1003.1-88 . +.Sh HISTORY +The +.Fn sysconf +function first appeared in +.Bx 4.4 . +.Sh BUGS +The value for _SC_STREAM_MAX is a minimum maximum, and required to be +the same as ANSI C's FOPEN_MAX, so the returned value is a ridiculously +small and misleading number. |