glibc/sysdeps/posix/sigblock.c

/* Copyright (C) 1991, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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 <signal.h>

/* Block signals in MASK, returning the old mask.  */
int
__sigblock (mask)
     int mask;
{
  register int sig;
  sigset_t set, oset;

  if (__sigemptyset (&set) < 0)
    return -1;

  if (sizeof (mask) == sizeof (set))
    *(int *) &set = mask;
  else if (sizeof (unsigned long int) == sizeof (set))
    *(unsigned long int *) &set = (unsigned int) mask;
  else
    for (sig = 1; sig < NSIG && sig <= sizeof (mask) * 8; ++sig)
      if ((mask & sigmask (sig)) && __sigaddset (&set, sig) < 0)
	return -1;

  if (sigprocmask (SIG_BLOCK, &set, &oset) < 0)
    return -1;

  if (sizeof (mask) == sizeof (oset))
    mask = *(int *) &oset;
  else if (sizeof (unsigned long int) == sizeof (oset))
    mask = *(unsigned long int*) &oset;
  else
    for (sig = 1, mask = 0; sig < NSIG && sig <= sizeof (mask) * 8; ++sig)
      if (__sigismember (&oset, sig))
	mask |= sigmask (sig);

  return mask;
}

weak_alias (__sigblock, sigblock)