glibc/signal/sighold.c

/* Add SIG to the calling process' signal mask.
   Copyright (C) 1998-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#define __need_NULL
#include <stddef.h>
#include <signal.h>

int
sighold (int sig)
{
  sigset_t set;

  /* Retrieve current signal set.  */
  if (__sigprocmask (SIG_SETMASK, NULL, &set) < 0)
    return -1;

  /* Add the specified signal.  */
  if (sigaddset (&set, sig) < 0)
    return -1;

  /* Set the new mask.  */
  return __sigprocmask (SIG_SETMASK, &set, NULL);
}