NAME
sysv_signal - signal handling with System V semantics
SYNOPSIS
#define _GNU_SOURCE
#include <signal.h>
typedef void (*sighandler_t)(int);
I sighandler_t sysv_signal(int signum , sighandler_t handler );
DESCRIPTION
The
R sysv_signal ()
function takes the same arguments, and performs the same task, as
signal(2).
However
R sysv_signal ()
provides the System V unreliable signal semantics, that is:
a) the disposition of the signal is reset to the default
when the handler is invoked;
b) delivery of further instances of the signal is not blocked while
the signal handler is executing; and
c) if the handler interrupts (certain) blocking system calls,
then the system call is not automatically restarted.
RETURN VALUE
The
R sysv_signal ()
function returns the previous value of the signal handler, or
SIG_ERR
on error.
ERRORS
CONFORMING TO
This function is non-standard.
NOTES
Use of
R sysv_signal ()
should be avoided; use
sigaction(2)
instead.
On older Linux systems,
R sysv_signal ()
and
signal(2)
were equivalent.
But on newer systems,
signal(2)
provides reliable 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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