NAME
bsd_signal - signal handling with BSD semantics
SYNOPSIS
#define _XOPEN_SOURCE
#include <signal.h>
typedef void (*sighandler_t)(int);
I sighandler_t bsd_signal(int signum , sighandler_t handler );
DESCRIPTION
The
R bsd_signal ()
function takes the same arguments, and performs the same task, as
signal(2).
The difference between the two is that
R bsd_signal ()
is guaranteed to provide reliable signal semantics, that is:
a) the disposition of the signal is not reset to the default
when the handler is invoked;
b) delivery of further instances of the signal is blocked while
the signal handler is executing; and
c) if the handler interrupts a blocking system call,
then the system call is automatically restarted.
A portable application cannot rely on
signal(2)
to provide these guarantees.
RETURN VALUE
The
R bsd_signal ()
function returns the previous value of the signal handler, or
SIG_ERR
on error.
ERRORS
CONFORMING TO
4.2BSD, POSIX.1-2001.
NOTES
Use of
R bsd_signal ()
should be avoided; use
sigaction(2)
instead.
On modern Linux systems,
R bsd_signal ()
and
signal(2)
are equivalent.
But on older systems,
signal(2)
provided unreliable signal semantics; see
signal(2)
for details.
The use of
sighandler_t
is a GNU extension;
this type is only defined if the
_GNU_SOURCE
feature test macro is defined.
SEE ALSO
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