libc/signal/sighold.c

   1 /* Add SIG to the calling process' signal mask.
   2    Copyright (C) 1998, 2000, 2003 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #define __need_NULL
  21 #include <stddef.h>
  22 #include <signal.h>
  23
  24 int sighold (int sig)
  25 {
  26   sigset_t set;
  27
  28   /* Retrieve current signal set.  */
  29   sigprocmask (SIG_SETMASK, NULL, &set); /* can't fail */
  30
  31   /* Bound-check sig, add it to the set.  */
  32   if (sigaddset (&set, sig) < 0)
  33     return -1;
  34
  35   /* Set the new mask.  */
  36   return sigprocmask (SIG_SETMASK, &set, NULL);
  37 }