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glibc  2.9
semctl.c
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00001 /* Copyright (C) 1995, 1997, 1998, 2000 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <errno.h>
00021 #include <stdarg.h>
00022 #include <sys/sem.h>
00023 #include <ipc_priv.h>
00024 
00025 #include <sysdep.h>
00026 #include <sys/syscall.h>
00027 
00028 /* Define a `union semun' suitable for Linux here.  */
00029 union semun
00030 {
00031   int val;                  /* value for SETVAL */
00032   struct semid_ds *buf;            /* buffer for IPC_STAT & IPC_SET */
00033   unsigned short int *array;       /* array for GETALL & SETALL */
00034   struct seminfo *__buf;    /* buffer for IPC_INFO */
00035 };
00036 
00037 #include <bp-checks.h>
00038 #include <bp-semctl.h>             /* definition of CHECK_SEMCTL needs union semum */
00039 
00040 /* Return identifier for array of NSEMS semaphores associated with
00041    KEY.  */
00042 
00043 int
00044 semctl (int semid, int semnum, int cmd, ...)
00045 {
00046   union semun arg;
00047   va_list ap;
00048 
00049   va_start (ap, cmd);
00050 
00051   /* Get the argument.  */
00052   arg = va_arg (ap, union semun);
00053 
00054   va_end (ap);
00055 
00056   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
00057                       CHECK_SEMCTL (&arg, semid, cmd)->array);
00058 }