sem.h

/* Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

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

#ifndef _SYS_SEM_H
#error "Never use <bits/sem.h> directly; include <sys/sem.h> instead."
#endif


#include <features.h>
#include <sys/types.h>

/* Flags for `semop'.  */
#define SEM_UNDO	0x1000		/* undo the operation on exit */

/* Commands for `semctl'.  */
#define GETPID		11		/* get sempid */
#define GETVAL		12		/* get semval */
#define GETALL		13		/* get all semval's */
#define GETNCNT		14		/* get semncnt */
#define GETZCNT		15		/* get semzcnt */
#define SETVAL		16		/* set semval */
#define SETALL		17		/* set all semval's */


__BEGIN_DECLS

/* Data structure describing a set of semaphores.  */
struct semid_ds
{
  struct ipc_perm sem_perm;		/* operation permission struct */
  __time_t sem_otime;			/* last semop() time */
  __time_t sem_ctime;			/* last time changed by semctl() */
  unsigned short int sem_nsems;		/* number of semaphores in set */
};

/* Union used for argument for `semctl'.  */
union semun
{
  int val;				/* value for SETVAL */
  struct semid_ds *buf;			/* buffer for IPC_STAT & IPC_SET */
  unsigned short int *array;		/* array for GETALL & SETALL */
  struct seminfo *__buf;		/* buffer for IPC_INFO */
 };

__END_DECLS