/* Convenience declarations when working with <signal.h>.

   Copyright (C) 2008-2019 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#ifndef _GL_SIG_HANDLER_H

#define _GL_SIG_HANDLER_H

#include <signal.h>

#ifndef _GL_INLINE_HEADER_BEGIN

 #error "Please include config.h first."

#endif

_GL_INLINE_HEADER_BEGIN

#ifndef SIG_HANDLER_INLINE

# define SIG_HANDLER_INLINE _GL_INLINE

#endif

/* Convenience type when working with signal handlers.  */

typedef void (*sa_handler_t) (int);

/* Return the handler of a signal, as a sa_handler_t value regardless

   of its true type.  The resulting function can be compared to

   special values like SIG_IGN but it is not portable to call it.  */

SIG_HANDLER_INLINE sa_handler_t _GL_ATTRIBUTE_PURE

get_handler (struct sigaction const *a)

{

  /* POSIX says that special values like SIG_IGN can only occur when

     action.sa_flags does not contain SA_SIGINFO.  But in Linux 2.4,

     for example, sa_sigaction and sa_handler are aliases and a signal

     is ignored if sa_sigaction (after casting) equals SIG_IGN.  In

     this case, this implementation relies on the fact that the two

     are aliases, and simply returns sa_handler.  */

  return a->sa_handler;

}

_GL_INLINE_HEADER_END

#endif /* _GL_SIG_HANDLER_H */