1/* Convenience declarations when working with <signal.h>.
2
3   Copyright (C) 2008-2012 Free Software Foundation, Inc.
4
5   This program is free software: you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program 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
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17
18#ifndef _GL_SIG_HANDLER_H
19#define _GL_SIG_HANDLER_H
20
21#include <signal.h>
22
23_GL_INLINE_HEADER_BEGIN
24#ifndef SIG_HANDLER_INLINE
25# define SIG_HANDLER_INLINE _GL_INLINE
26#endif
27
28/* Convenience type when working with signal handlers.  */
29typedef void (*sa_handler_t) (int);
30
31/* Return the handler of a signal, as a sa_handler_t value regardless
32   of its true type.  The resulting function can be compared to
33   special values like SIG_IGN but it is not portable to call it.  */
34SIG_HANDLER_INLINE sa_handler_t
35get_handler (struct sigaction const *a)
36{
37#ifdef SA_SIGINFO
38  /* POSIX says that special values like SIG_IGN can only occur when
39     action.sa_flags does not contain SA_SIGINFO.  But in Linux 2.4,
40     for example, sa_sigaction and sa_handler are aliases and a signal
41     is ignored if sa_sigaction (after casting) equals SIG_IGN.  So
42     use (and cast) sa_sigaction in that case.  */
43  if (a->sa_flags & SA_SIGINFO)
44    return (sa_handler_t) a->sa_sigaction;
45#endif
46  return a->sa_handler;
47}
48
49_GL_INLINE_HEADER_END
50
51#endif /* _GL_SIG_HANDLER_H */
52