BSD_SIGNAL(3) | Library Functions Manual | BSD_SIGNAL(3) |
bsd_signal
—
simplified signal facilities
#include
<signal.h>
void (*
bsd_signal
(int
sig, void
(*func)(int)))(int);
or in an equivalent but easier to read typedef'd version:
typedef void (*sig_t) (int);
sig_t
bsd_signal
(int
sig, sig_t
func);
The
bsd_signal
()
function provides a partially compatible interface for programs written to
historical system interfaces (see USAGE below).
The function call
bsd_signal
(sig,
func) has the effect as if implemented as:
void (*bsd_signal(int sig, void (*func)(int)))(int) { struct sigaction act, oact; act.sa_handler = func; act.sa_flags = SA_RESTART; sigemptyset(&act.sa_mask); sigaddset(&act.sa_mask, sig); if (sigaction(sig, &act, &oact) == -1) return(SIG_ERR); return(oact.sa_handler); }
The handler function should be declared:
func
(int
sig)where sig is the signal number.
The behavior is undefined if
func
() is a
function that takes more than one argument, or an argument of a different
type.
Upon successful completion, bsd_signal
()
returns the previous action for sig. Otherwise,
SIG_ERR
is returned and errno
is set to indicate the error.
Refer to sigaction(2).
This function is a direct replacement for the
BSD
signal(3) function for simple
applications that are installing a single-argument signal handler function.
If a BSD signal handler function is being installed
that expects more than one argument, the application has to be modified to
use sigaction(2). The
bsd_signal
() function differs from
signal(3) in that the
SA_RESTART
flag is set and the
SA_RESETHAND
will be clear when
bsd_signal
() is used. The state of these flags is
not specified for signal(3).
The bsd_signal
() function conforms to
IEEE Std 1003.1-2001 (“POSIX.1”).
December 20, 2003 | macOS 14.6 |