2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
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9.2 KiB
Groff
329 lines
9.2 KiB
Groff
.\" $NetBSD: sysconf.3,v 1.37 2010/03/22 19:30:54 joerg Exp $
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.\"
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.\" Copyright (c) 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)sysconf.3 8.3 (Berkeley) 4/19/94
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.\"
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.Dd August 6, 2008
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.Dt SYSCONF 3
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.Os
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.Sh NAME
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.Nm sysconf
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.Nd get configurable system variables
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft long
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.Fn sysconf "int name"
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.Sh DESCRIPTION
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This interface is defined by
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.St -p1003.1-88 .
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A far more complete interface is available using
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.Xr sysctl 3 .
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.Pp
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The
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.Fn sysconf
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function provides a method for applications to determine the current
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value of a configurable system limit or option variable.
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The
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.Fa name
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argument specifies the system variable to be queried.
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Symbolic constants for each name value are found in the include file
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.In unistd.h .
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.Pp
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The available values are as follows:
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.Bl -tag -width "123456"
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.It Li _SC_ARG_MAX
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The maximum bytes of argument to
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.Xr execve 2 .
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.It Li _SC_ATEXIT_MAX
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The maxmimum number of functions that may be registered with
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.Xr atexit 3 .
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.It Li _SC_BARRIERS
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The version of
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.St -p1003.1
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and its
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Barriers
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option to which the system attempts to conform,
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otherwise \-1.
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.It Li _SC_CLOCK_SELECTION
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Return the
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.Tn POSIX
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version the implementation of the Clock Selection Option
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on this system conforms to,
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or \-1 if unavailable.
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.It Li _SC_CHILD_MAX
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The maximum number of simultaneous processes per user id.
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.It Li _SC_CLK_TCK
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The number of clock ticks per second.
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.It Li _SC_FSYNC
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Return 1 if the File Synchronization Option is available on this system,
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otherwise \-1.
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.It Li _SC_HOST_NAME_MAX
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The maximum size of a hostname, including NULL.
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.It Li _SC_IOV_MAX
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The maximum number of
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.Va iovec
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structures that a process has available for use with
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.Xr preadv 2 ,
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.Xr pwritev 2 ,
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.Xr readv 2 ,
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.Xr recvmsg 2 ,
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.Xr sendmsg 2
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or
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.Xr writev 2 .
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.It Li _SC_JOB_CONTROL
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Return 1 if job control is available on this system, otherwise \-1.
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.It Li _SC_LOGIN_NAME_MAX
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Returns the size of the storage required for a login name, in bytes,
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including the terminating NUL.
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.It Li _SC_MAPPED_FILES
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Return 1 if the Memory Mapped Files Option is available on this system,
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otherwise \-1.
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.It Li _SC_MEMLOCK
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Return 1 if the Process Memory Locking Option is available on this system,
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otherwise \-1.
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.It Li _SC_MEMLOCK_RANGE
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Return 1 if the Range Memory Locking Option is available on this system,
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otherwise \-1.
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.It Li _SC_MEMORY_PROTECTION
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Return 1 if the Memory Protection Option is available on this system,
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otherwise \-1.
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.It Li _SC_MONOTONIC_CLOCK
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Return the
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.Tn POSIX
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version the implementation of the Monotonic Clock Option
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on this system conforms to,
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or \-1 if unavailable.
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.It Li _SC_NGROUPS_MAX
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The maximum number of supplemental groups.
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.It Li _SC_OPEN_MAX
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The maximum number of open files per process.
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.It Li _SC_PAGESIZE
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The size of a system page in bytes.
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.It Li _SC_PASS_MAX
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The maximum length of the password, not counting NULL.
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.It Li _SC_READER_WRITER_LOCKS
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The version of
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.St -p1003.1
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and its
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Read-Write Locks
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option to which the system attempts to conform,
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otherwise \-1.
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.It Li _SC_REGEXP
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Return 1 if
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.Tn POSIX
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regular expressions are available on this system, otherwise \-1.
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.It Li _SC_SEMAPHORES
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The version of
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.St -p1003.1
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and its
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Semaphores
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option to which the system attempts to conform,
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otherwise \-1.
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.Pp
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Availability of the
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Semaphores
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option depends on the
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.Li P1003_1B_SEMAPHORE
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kernel option.
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.It Li _SC_SHELL
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Return 1 if
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.Tn POSIX
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shell is available on this system, otherwise \-1.
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.It Li _SC_SPIN_LOCKS
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The version of
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.St -p1003.1
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and its
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Spin Locks
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option to which the system attempts to conform,
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otherwise \-1.
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.It Li _SC_STREAM_MAX
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The minimum maximum number of streams that a process may have open
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at any one time.
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.It Li _SC_SYMLOOP_MAX
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The maximum number of symbolic links that may be expanded in a path name.
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.It Li _SC_SYNCHRONIZED_IO
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Return 1 if the Synchronized I/O Option is available on this system,
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otherwise \-1.
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.It Li _SC_THREADS
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The version of
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.St -p1003.1
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and its
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Threads
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option to which the system attempts to conform,
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otherwise \-1.
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.It Li _SC_TIMERS
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The version of
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.St -p1003.1
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and its
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Timers
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option to which the system attempts to conform,
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otherwise \-1.
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.It Li _SC_TZNAME_MAX
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The minimum maximum number of types supported for the name of a
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timezone.
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.It Li _SC_SAVED_IDS
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Returns 1 if saved set-group and saved set-user ID is available,
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otherwise \-1.
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.It Li _SC_VERSION
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The version of ISO/IEC 9945 (POSIX 1003.1) with which the system
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attempts to comply.
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.It Li _SC_XOPEN_SHM
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Return 1 if the
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.St -xpg4.2
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Shared Memory
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option is available on this system,
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otherwise \-1.
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.Pp
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Availability of the
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Shared Memory
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option depends on the
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.Li SYSVSHM
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kernel option.
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.It Li _SC_BC_BASE_MAX
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The maximum ibase/obase values in the
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.Xr bc 1
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utility.
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.It Li _SC_BC_DIM_MAX
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The maximum array size in the
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.Xr bc 1
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utility.
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.It Li _SC_BC_SCALE_MAX
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The maximum scale value in the
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.Xr bc 1
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utility.
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.It Li _SC_BC_STRING_MAX
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The maximum string length in the
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.Xr bc 1
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utility.
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.It Li _SC_COLL_WEIGHTS_MAX
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The maximum number of weights that can be assigned to any entry of
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the LC_COLLATE order keyword in the locale definition file.
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.It Li _SC_EXPR_NEST_MAX
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The maximum number of expressions that can be nested within
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parenthesis by the
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.Xr expr 1
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utility.
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.It Li _SC_LINE_MAX
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The maximum length in bytes of a text-processing utility's input
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line.
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.It Li _SC_RE_DUP_MAX
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The maximum number of repeated occurrences of a regular expression
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permitted when using interval notation.
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.It Li _SC_2_VERSION
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The version of POSIX 1003.2 with which the system attempts to comply.
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.It Li _SC_2_C_BIND
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Return 1 if the system's C-language development facilities support the
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C-Language Bindings Option, otherwise \-1.
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.It Li _SC_2_C_DEV
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Return 1 if the system supports the C-Language Development Utilities Option,
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otherwise \-1.
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.It Li _SC_2_CHAR_TERM
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Return 1 if the system supports at least one terminal type capable of
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all operations described in POSIX 1003.2, otherwise \-1.
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.It Li _SC_2_FORT_DEV
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Return 1 if the system supports the FORTRAN Development Utilities Option,
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otherwise \-1.
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.It Li _SC_2_FORT_RUN
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Return 1 if the system supports the FORTRAN Runtime Utilities Option,
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otherwise \-1.
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.It Li _SC_2_LOCALEDEF
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Return 1 if the system supports the creation of locales, otherwise \-1.
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.It Li _SC_2_SW_DEV
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Return 1 if the system supports the Software Development Utilities Option,
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otherwise \-1.
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.It Li _SC_2_UPE
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Return 1 if the system supports the User Portability Utilities Option,
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otherwise \-1.
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.It Li _SC_GETGR_R_SIZE_MAX
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The minimum size of the
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.Fa buffer
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passed to
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.Xr getgrgid_r 3
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and
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.Xr getgrnam_r 3 .
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.It Li _SC_GETPW_R_SIZE_MAX
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The minimum size of the
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.Fa buffer
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passed to
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.Xr getpwnam_r 3
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and
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.Xr getpwuid_r 3 .
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.It Li _SC_NPROCESSORS_CONF
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The number of processors configured.
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.It Li _SC_NPROCESSORS_ONLN
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The number of processors online (capable of running processes).
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.El
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.Sh RETURN VALUES
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If the call to
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.Nm sysconf
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is not successful, \-1 is returned and
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.Va errno
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is set appropriately.
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Otherwise, if the variable is associated with functionality that is not
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supported, \-1 is returned and
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.Va errno
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is not modified.
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Otherwise, the current variable value is returned.
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.Sh ERRORS
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The
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.Fn sysconf
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function may fail and set
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.Va errno
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for any of the errors specified for the library functions
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.Xr sysctl 3 .
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In addition, the following error may be reported:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The value of the
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.Fa name
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argument is invalid.
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.El
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.Sh SEE ALSO
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.Xr sysctl 3
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.Sh STANDARDS
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The
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.Fn sysconf
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function conforms to
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.St -p1003.1-90 .
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The constants
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.Li _SC_NPROCESSORS_CONF
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and
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.Li _SC_NPROCESSORS_ONLN
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are not part of the standard, but are provided by many systems.
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.Sh HISTORY
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The
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.Nm sysconf
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function first appeared in
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.Bx 4.4 .
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.Sh BUGS
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The value for _SC_STREAM_MAX is a minimum maximum, and required to be
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the same as ANSI C's FOPEN_MAX, so the returned value is a ridiculously
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small and misleading number.
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