Section: POSIX Programmer's Manual (3P)
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.
--- test for a signal in a signal set
int sigismember(const sigset_t *set, int signo);
function shall test whether the signal specified by
is a member of the set pointed to by
Applications should call either
at least once for each object of type
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
the results are undefined.
Upon successful completion,
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
to indicate the error.
function may fail if:
argument is not a valid signal number, or is an unsupported signal
The following sections are informative.
, Signal Concepts,
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
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