sysdeps/pthread/semaphore.h

   1 /* Copyright (C) 2002-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _SEMAPHORE_H
  19 #define _SEMAPHORE_H    1
  20
  21 #include <features.h>
  22 #include <sys/types.h>
  23 #ifdef __USE_XOPEN2K
  24 # include <bits/types/struct_timespec.h>
  25 #endif
  26
  27 /* Get the definition for sem_t.  */
  28 #include <bits/semaphore.h>
  29
  30
  31 __BEGIN_DECLS
  32
  33 /* Initialize semaphore object SEM to VALUE.  If PSHARED then share it
  34    with other processes.  */
  35 extern int sem_init (sem_t *__sem, int __pshared, unsigned int __value)
  36   __THROW __nonnull ((1));
  37
  38 /* Free resources associated with semaphore object SEM.  */
  39 extern int sem_destroy (sem_t *__sem) __THROW __nonnull ((1));
  40
  41 /* Open a named semaphore NAME with open flags OFLAG.  */
  42 extern sem_t *sem_open (const char *__name, int __oflag, ...)
  43   __THROW __nonnull ((1));
  44
  45 /* Close descriptor for named semaphore SEM.  */
  46 extern int sem_close (sem_t *__sem) __THROW __nonnull ((1));
  47
  48 /* Remove named semaphore NAME.  */
  49 extern int sem_unlink (const char *__name) __THROW __nonnull ((1));
  50
  51 /* Wait for SEM being posted.
  52
  53    This function is a cancellation point and therefore not marked with
  54    __THROW.  */
  55 extern int sem_wait (sem_t *__sem) __nonnull ((1));
  56
  57 #ifdef __USE_XOPEN2K
  58 /* Similar to `sem_wait' but wait only until ABSTIME.
  59
  60    This function is a cancellation point and therefore not marked with
  61    __THROW.  */
  62 # ifndef __USE_TIME64_REDIRECTS
  63 extern int sem_timedwait (sem_t *__restrict __sem,
  64                           const struct timespec *__restrict __abstime)
  65   __nonnull ((1, 2));
  66 # else
  67 #  ifdef __REDIRECT
  68 extern int __REDIRECT (sem_timedwait,
  69                        (sem_t *__restrict __sem,
  70                         const struct timespec *__restrict __abstime),
  71                         __sem_timedwait64)
  72   __nonnull ((1, 2));
  73 #  else
  74 #   define sem_timedwait __sem_timedwait64
  75 #  endif
  76 # endif
  77 #endif
  78
  79 #ifdef __USE_GNU
  80 # ifndef __USE_TIME64_REDIRECTS
  81 extern int sem_clockwait (sem_t *__restrict __sem,
  82                           clockid_t clock,
  83                           const struct timespec *__restrict __abstime)
  84   __nonnull ((1, 3));
  85 # else
  86 #  ifdef __REDIRECT
  87 extern int __REDIRECT (sem_clockwait,
  88                        (sem_t *__restrict __sem,
  89                         clockid_t clock,
  90                         const struct timespec *__restrict __abstime),
  91                         __sem_clockwait64)
  92   __nonnull ((1, 3));
  93 #  else
  94 #   define sem_clockwait __sem_clockwait64
  95 #  endif
  96 # endif
  97 #endif
  98
  99 /* Test whether SEM is posted.  */
 100 extern int sem_trywait (sem_t *__sem) __THROWNL __nonnull ((1));
 101
 102 /* Post SEM.  */
 103 extern int sem_post (sem_t *__sem) __THROWNL __nonnull ((1));
 104
 105 /* Get current value of SEM and store it in *SVAL.  */
 106 extern int sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval)
 107   __THROW __nonnull ((1, 2));
 108
 109
 110 __END_DECLS
 111
 112 #endif  /* semaphore.h */