BSD_SIGNAL(3) Library Functions Manual BSD_SIGNAL(3)

NAME

bsd_signal — simplified signal facilities

SYNOPSIS

#include <signal.h>

void (*bsd_signal(int sig, void (*func)(int)))(int);

DESCRIPTION

The bsd_signal() function provides a partially compatible interface for programs written to historical system interfaces (see APPLICATION USAGE below).

The function call bsd_signal ( sig, func) has an 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: void handler(int sig); where sig is the signal number. The behaviour is undefined if func is a function that takes more than one argument, or an argument of a different type.

RETURN VALUE

Upon successful completion, bsd_signal() returns the previous action for sig . Otherwise, SIG_ERR is returned and errno is set to indicate the error.

ERRORS

Refer to sigaction(3) .

EXAMPLES

None.

APPLICATION USAGE

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(3) . 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) .

FUTURE DIRECTIONS

None.