sysv_signal — signal handling with System V semantics
#define _GNU_SOURCE #include <signal.h> typedef void (*sighandler_t)(int);
sighandler_t sysv_signal( |
int signum, |
sighandler_t handler); |
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.
The sysv_signal() function
returns the previous value of the signal handler, or
SIG_ERR on error.
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.