1/* Convenience declarations when working with <signal.h>.
2
3   Copyright (C) 2008-2014 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#ifndef _GL_INLINE_HEADER_BEGIN
24 #error "Please include config.h first."
25#endif
26_GL_INLINE_HEADER_BEGIN
27#ifndef SIG_HANDLER_INLINE
28# define SIG_HANDLER_INLINE _GL_INLINE
29#endif
30
31/* Convenience type when working with signal handlers.  */
32typedef void (*sa_handler_t) (int);
33
34/* Return the handler of a signal, as a sa_handler_t value regardless
35   of its true type.  The resulting function can be compared to
36   special values like SIG_IGN but it is not portable to call it.  */
37SIG_HANDLER_INLINE sa_handler_t
38get_handler (struct sigaction const *a)
39{
40#ifdef SA_SIGINFO
41  /* POSIX says that special values like SIG_IGN can only occur when
42     action.sa_flags does not contain SA_SIGINFO.  But in Linux 2.4,
43     for example, sa_sigaction and sa_handler are aliases and a signal
44     is ignored if sa_sigaction (after casting) equals SIG_IGN.  So
45     use (and cast) sa_sigaction in that case.  */
46  if (a->sa_flags & SA_SIGINFO)
47    return (sa_handler_t) a->sa_sigaction;
48#endif
49  return a->sa_handler;
50}
51
52_GL_INLINE_HEADER_END
53
54#endif /* _GL_SIG_HANDLER_H */
55