nptl/pthread_mutexattr_setpshared.c

   1 /* Copyright (C) 2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <pthreadP.h>
  22
  23
  24 int
  25 pthread_mutexattr_setpshared (attr, pshared)
  26      pthread_mutexattr_t *attr;
  27      int pshared;
  28 {
  29   struct pthread_mutexattr *iattr;
  30
  31   if (pshared != PTHREAD_PROCESS_PRIVATE
  32       && __builtin_expect (pshared != PTHREAD_PROCESS_SHARED, 0))
  33     return EINVAL;
  34
  35   iattr = (struct pthread_mutexattr *) attr;
  36
  37   /* We use bit 31 to signal whether the mutex is going to be
  38      process-shared or not.  */
  39   if (pshared == PTHREAD_PROCESS_PRIVATE)
  40     iattr->mutexkind &= ~0x80000000;
  41   else
  42     iattr->mutexkind |= 0x80000000;
  43
  44   return 0;
  45 }