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nano-7.2/lib/sig-handler.h

52 lines
1.9 KiB
C

/* Convenience declarations when working with <signal.h>.
Copyright (C) 2008-2023 Free Software Foundation, Inc.
This file 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.
This file 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 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 */