HP-UX Reference (11i v1 05/09) - 3 Library Functions A-M (vol 6)

bsd_signal(3C) bsd_signal(3C)

(TO BE OBSOLETED)

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() .

APPLICATION USAGE

This function is a direct replacement for the BSD signal() function for simple applications that are ins-

talling 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()

. The

bsd_signal() function differs from signal() 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().

WARNINGS

Obsolescent Interfaces

bsd_signal() is to be obsoleted at a future date.