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BSD_SIGNAL(3) BSD 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); 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); DESCRIPTION
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: void 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. RETURN VALUES
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(2). 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 modi- fied 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). SEE ALSO
sigaction(2), sigaddset(3), sigemptyset(3), signal(3) STANDARDS
The bsd_signal() function conforms to IEEE Std 1003.1-2001 (``POSIX.1''). BSD
December 20, 2003 BSD
