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.
sigismember — test for a signal in a signal set
int sigismember(const sigset_t *set, int signo);
The sigismember() function shall test whether the signal specified by
signo is a member of the set pointed to by set.
Applications should 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.
Upon successful completion, sigismember() shall return 1 if the specified
signal is a member of the specified set, or 0 if it is not. Otherwise, it
shall return -1 and set errno to indicate the error.
The sigismember() function may fail if:
- The signo argument is not a valid signal number, or is an
unsupported signal number.
The following sections are informative.
Section 2.4, Signal Concepts, pthread_sigmask(),
The Base Definitions volume of POSIX.1‐2017,
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 .
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