BSD_SIGNAL(3P) POSIX Programmer's Manual BSD_SIGNAL(3P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
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).
The function call bsd_signal(sig, func) shall be equivalent to the following:
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 behavior is undefined if func is a function that takes more than one argument, or an argument of a dif-
ferent type.
RETURN VALUE
Upon successful completion, bsd_signal() shall return the previous action for sig. Otherwise, SIG_ERR shall be returned and errno shall be
set to indicate the error.
ERRORS
Refer to sigaction().
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
This function is a direct replacement for the BSD signal() 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(). The bsd_signal() function differs from signal() in that the SA_RESTART flag is set and the SA_RESETHAND is clear
when bsd_signal() is used. The state of these flags is not specified for signal().
It is recommended that new applications use the sigaction() function.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
sigaction(), sigaddset(), sigemptyset(), signal(), the Base Definitions volume of IEEE Std 1003.1-2001, <signal.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
online at http://www.opengroup.org/unix/online.html .
IEEE
/The Open Group 2003 BSD_SIGNAL(3P)