sem.c

linux下用PCMCIA无线网卡虚拟无线AP的程序源码

/* Copyright (C) 1995, 1997, 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <[e-mail]>, 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.  */

#include <errno.h>
#include <sys/sem.h>
#include "ipc.h"

#ifdef L_semctl
/* Return identifier for array of NSEMS semaphores associated with
   KEY.  */
#include <stdarg.h>
/* Define a `union semun' suitable for Linux here.  */
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 */
};


int
semctl (int semid, int semnum, int cmd, ...)
{
    union semun arg;
    va_list ap;

    va_start (ap, cmd);

    /* Get the argument.  */
    arg = va_arg (ap, union semun);

    va_end (ap);

    return __ipc(IPCOP_semctl, semid, semnum, cmd, &arg);
}    
#endif

#ifdef L_semget
#include <stdlib.h>		/* for definition of NULL */
/* Return identifier for array of NSEMS semaphores associated with
   KEY.  */
int
semget (key, nsems, semflg)
    key_t key;
    int nsems;
    int semflg;
{
    return __ipc(IPCOP_semget, key, nsems, semflg, NULL);
}
#endif

#ifdef L_semop
/* Perform user-defined atomical operation of array of semaphores.  */
int
semop (semid, sops, nsops)
    int semid;
    struct sembuf *sops;
    size_t nsops;
{
    return __ipc(IPCOP_semop, semid, (int) nsops, 0, sops);
}
#endif