SIGADDSET(3P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME
sigaddset — add a signal to a signal set

SYNOPSIS

#include <signal.h>

int sigaddset(sigset_t *set, int signo);

DESCRIPTION
The sigaddset() function adds the individual signal specified by the signo to the signal set pointed to by set.

Applications shall call either sigemptyset() or sigfillset() at least once for each object of type sigset_t prior to any other use of that object. If such an object is not initialized in this way, but is nonetheless supplied as an argument to any of pthread_sigmask(), sigaction(), sigaddset(), sigdelset(), sigismember(), sigpending(), sigprocmask(), sigsuspend(), sigtimedwait(), sigwait(), or sigwaitinfo(), the results are undefined.

RETURN VALUE
Upon successful completion, sigaddset() shall return 0; otherwise, it shall return -1 and set errno to indicate the error.

ERRORS
The sigaddset() function may fail if:

EINVAL
    The value of the signo argument is an invalid or unsupported signal number.

The following sections are informative.

EXAMPLES
None.

APPLICATION USAGE
None.

RATIONALE
None.

FUTURE DIRECTIONS
None.

SEE ALSO
Section 2.4, Signal Concepts, pthread_sigmask(), sigaction(), sigdelset(), sigemptyset(), sigfillset(), sigismember(), sigpending(), sigsuspend()

The Base Definitions volume of POSIX.1-2017, <signal.h>

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .