SYSV_SIGNAL(2)

NAME
sysv_signal - signal handling with System V semantics

SYNOPSIS
#define _GNU_SOURCE
#include <signal.h>

typedef void (*sighandler_t)(int);

sighandler_t sysv_signal(int signum, sighandler_t handler);

DESCRIPTION
The sysv_signal() function takes the same arguments, and performs the same task, as signal(2). However 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 sysv_signal() function returns the previous value of the signal handler, or SIG_ERR on error.

ERRORS
As for signal(2).

NOTES
Use of sysv_signal() should be avoided; use sigaction(2) instead. On older Linux systems, 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.

CONFORMING TO
This function is non-standard.

SEE ALSO
sigaction(2), signal(2), bsd_signal(3), feature_test_macros(7), signal(7)