sysdeps/unix/sysv/linux/shmat.c

   1 /* Copyright (C) 1995, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <sys/shm.h>
  21
  22 /* Attach the shared memory segment associated with SHMID to the data
  23    segment of the calling process.  SHMADDR and SHMFLG determine how
  24    and where the segment is attached.  */
  25
  26 void *
  27 shmat (shmid, shmaddr, shmflg)
  28      int shmid;
  29      const void *shmaddr;
  30      int shmflg;
  31 {
  32   int retval;
  33   unsigned long raddr;
  34
  35   retval = __ipc (IPCOP_shmat, shmid, shmflg, (int) &raddr, (void *) shmaddr);
  36   return ((unsigned long int) retval > -(unsigned long int) SHMLBA
  37           ? (void *) retval : (void *) raddr);
  38 }