sysdeps/posix/signal.c

   1 /* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <signal.h>
  22
  23
  24 sigset_t _sigintr;              /* Set by siginterrupt.  */
  25
  26 /* Set the handler for the signal SIG to HANDLER,
  27    returning the old handler, or SIG_ERR on error.  */
  28 __sighandler_t
  29 DEFUN(signal, (sig, handler), int sig AND __sighandler_t handler)
  30 {
  31   struct sigaction act, oact;
  32
  33   if (handler == SIG_ERR)
  34     {
  35       errno = EINVAL;
  36       return SIG_ERR;
  37     }
  38
  39   act.sa_handler = handler;
  40   if (__sigemptyset (&act.sa_mask) < 0)
  41     return SIG_ERR;
  42   act.sa_flags = __sigismember (&_sigintr, sig) ? 0 : SA_RESTART;
  43   if (__sigaction (sig, &act, &oact) < 0)
  44     return SIG_ERR;
  45
  46   return oact.sa_handler;
  47 }