sysconf.c

Glibc 2.3.2源代码(解压后有100多M)

/* Copyright (C) 1993, 1995, 1996, 1997, 2002 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Brendan Kehoe ([e-mail]).

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include <stdio.h>
#include <time.h>
#include <sysconfig.h>

extern int __sysconfig __P ((int));

/* Get the value of the system variable NAME.  */
long int
__sysconf (name)
     int name;
{
  switch (name)
    {
    default:
      __set_errno (EINVAL);
      return -1;

    case _SC_ARG_MAX:
#ifdef	ARG_MAX
      return ARG_MAX;
#else
      return -1;
#endif

    case _SC_CHILD_MAX:
#ifdef	CHILD_MAX
      return CHILD_MAX;
#else
      return -1;
#endif

    case _SC_CLK_TCK:
      return __sysconfig (_CONFIG_CLK_TCK);

    case _SC_NGROUPS_MAX:
#ifdef	NGROUPS_MAX
      return NGROUPS_MAX;
#else
      return -1;
#endif

      /* Both of these are looking for _CONFIG_OPEN_FILES.  */
    case _SC_OPEN_MAX:
    case _SC_STREAM_MAX:
      return __sysconfig (_CONFIG_OPEN_FILES);

    case _SC_TZNAME_MAX:
      return __tzname_max ();

    case _SC_JOB_CONTROL:
#ifdef	_POSIX_JOB_CONTROL
      return 1;
#else
      return -1;
#endif

    case _SC_SAVED_IDS:
#ifdef	_POSIX_SAVED_IDS
      return 1;
#else
      return -1;
#endif

    case _SC_REALTIME_SIGNALS:
#ifdef	_POSIX_REALTIME_SIGNALS
      return 1;
#else
      return -1;
#endif

    case _SC_PRIORITY_SCHEDULING:
#ifdef	_POSIX_PRIORITY_SCHEDULING
      return 1;
#else
      return -1;
#endif

    case _SC_TIMERS:
#ifdef	_POSIX_TIMERS
      return 1;
#else
      return -1;
#endif

    case _SC_ASYNCHRONOUS_IO:
#ifdef	_POSIX_ASYNCHRONOUS_IO
      return 1;
#else
      return -1;
#endif

    case _SC_PRIORITIZED_IO:
#ifdef	_POSIX_PRIORITIZED_IO
      return 1;
#else
      return -1;
#endif

    case _SC_SYNCHRONIZED_IO:
#ifdef	_POSIX_SYNCHRONIZED_IO
      return 1;
#else
      return -1;
#endif

    case _SC_FSYNC:
#ifdef	_POSIX_FSYNC
      return 1;
#else
      return -1;
#endif

    case _SC_MAPPED_FILES:
#ifdef	_POSIX_MAPPED_FILES
      return 1;
#else
      return -1;
#endif

    case _SC_MEMLOCK:
#ifdef	_POSIX_MEMLOCK
      return 1;
#else
      return -1;
#endif

    case _SC_MEMLOCK_RANGE:
#ifdef	_POSIX_MEMLOCK_RANGE
      return 1;
#else
      return -1;
#endif

    case _SC_MEMORY_PROTECTION:
#ifdef	_POSIX_MEMORY_PROTECTION
      return 1;
#else
      return -1;
#endif

    case _SC_MESSAGE_PASSING:
#ifdef	_POSIX_MESSAGE_PASSING
      return 1;
#else
      return -1;
#endif

    case _SC_SEMAPHORES:
#ifdef	_POSIX_SEMAPHORES
      return 1;
#else
      return -1;
#endif

    case _SC_SHARED_MEMORY_OBJECTS:
#ifdef	_POSIX_SHARED_MEMORY_OBJECTS
      return 1;
#else
      return -1;
#endif

    case _SC_VERSION:
      return _POSIX_VERSION;

    case _SC_PAGESIZE:
      return __sysconfig (_CONFIG_PAGESIZE);

    case _SC_AIO_LISTIO_MAX:
#ifdef	AIO_LISTIO_MAX
      return AIO_LISTIO_MAX;
#else
      return -1;
#endif

    case _SC_AIO_MAX:
#ifdef	AIO_MAX
      return AIO_MAX;
#else
      return -1;
#endif

    case _SC_AIO_PRIO_DELTA_MAX:
#ifdef	AIO_PRIO_DELTA_MAX
      return AIO_PRIO_DELTA_MAX;
#else
      return -1;
#endif

    case _SC_DELAYTIMER_MAX:
#ifdef	DELAYTIMER_MAX
      return DELAYTIMER_MAX;
#else
      return -1;
#endif

    case _SC_MQ_OPEN_MAX:
#ifdef	MQ_OPEN_MAX
      return MQ_OPEN_MAX;
#else
      return -1;
#endif

    case _SC_MQ_PRIO_MAX:
#ifdef	MQ_PRIO_MAX
      return MQ_PRIO_MAX;
#else
      return -1;
#endif

    case _SC_RTSIG_MAX:
#ifdef	RTSIG_MAX
      return RTSIG_MAX;
#else
      return -1;
#endif

    case _SC_SEM_NSEMS_MAX:
#ifdef	SEM_NSEMS_MAX
      return SEM_NSEMS_MAX;
#else
      return -1;
#endif

    case _SC_SEM_VALUE_MAX:
#ifdef	SEM_VALUE_MAX
      return SEM_VALUE_MAX;
#else
      return -1;
#endif

    case _SC_SIGQUEUE_MAX:
#ifdef	SIGQUEUE_MAX
      return SIGQUEUE_MAX;
#else
      return -1;
#endif

    case _SC_TIMER_MAX:
#ifdef	TIMER_MAX
      return TIMER_MAX;
#else
      return -1;
#endif

    case _SC_BC_BASE_MAX:
#ifdef	BC_BASE_MAX
      return BC_BASE_MAX;
#else
      return -1;
#endif

    case _SC_BC_DIM_MAX:
#ifdef	BC_DIM_MAX
      return BC_DIM_MAX;
#else
      return -1;
#endif

    case _SC_BC_SCALE_MAX:
#ifdef	BC_SCALE_MAX
      return BC_SCALE_MAX;
#else
      return -1;
#endif

    case _SC_BC_STRING_MAX:
#ifdef	BC_STRING_MAX
      return BC_STRING_MAX;
#else
      return -1;
#endif

    case _SC_EQUIV_CLASS_MAX:
#ifdef	EQUIV_CLASS_MAX
      return EQUIV_CLASS_MAX;
#else
      return -1;
#endif

    case _SC_EXPR_NEST_MAX:
#ifdef	EXPR_NEST_MAX
      return EXPR_NEST_MAX;
#else
      return -1;
#endif

    case _SC_LINE_MAX:
#ifdef	LINE_MAX
      return LINE_MAX;
#else
      return -1;
#endif

    case _SC_RE_DUP_MAX:
#ifdef	RE_DUP_MAX
      return RE_DUP_MAX;
#else
      return -1;
#endif

    case _SC_CHARCLASS_NAME_MAX:
#ifdef	CHARCLASS_NAME_MAX
      return CHARCLASS_NAME_MAX;
#else
      return -1;
#endif

    case _SC_2_VERSION:
      /* This is actually supposed to return the version
	 of the 1003.2 utilities on the system {POSIX2_VERSION}.  */
      return _POSIX2_C_VERSION;

    case _SC_2_C_BIND:
#ifdef	_POSIX2_C_BIND
      return _POSIX2_C_BIND;
#else
      return -1;
#endif

    case _SC_2_C_DEV:
#ifdef	_POSIX2_C_DEV
      return _POSIX2_C_DEV;
#else
      return -1;
#endif

    case _SC_2_FORT_DEV:
#ifdef	_POSIX2_FORT_DEV
      return _POSIX2_FORT_DEV;
#else
      return -1;
#endif

    case _SC_2_SW_DEV:
#ifdef	_POSIX2_SW_DEV
      return _POSIX2_SW_DEV;
#else
      return -1;
#endif
    }
}

weak_alias (__sysconf, sysconf)
libc_hidden_def (__sysconf)