Open System Services Library Calls Reference Manual (G06.28+, H06.05+)

sigismember(3) OSS Library Calls Reference Manual
NAME
sigismember - Tests for a signal in a signal set
LIBRARY
G-series native OSS processes: system library
H-series OSS processes: implicit libraries
SYNOPSIS
#include <signal.h>
int sigismember (
sigset_t *set,
int sig_number );
PARAMETERS
set Points to the signal set to be checked.
sig_number Specifies the signal to be tested for in the set.
DESCRIPTION
The sigismember() function tests whether the signal specified by the sig_number parameter is a
member of the signal set pointed to by the set parameter.
This function operates on data objects that can be addressed by the application, not on any set of
signals known to the system. This function is not for operations on the set of signals blocked
from delivery to a process or the set pending for a process.
A call to either the sigfillset() or sigemptyset() function must be made at least once for each
object of the type sigset_t before the sigismember() function is used on that set. If the object is
used without such initialization, the results are undefined.
RETURN VALUES
Upon successful completion, the sigismember() function returns the value 1 if the specified sig-
nal is a member of the specified set or the value 0 (zero) if it is not. If an error is detected, the
value -1 is returned and errno is set to indicate the error.
ERRORS
If the following condition occurs, the sigismember() function sets errno to the corresponding
value:
[EINVAL] The value of the sig_number parameter is an invalid or unsupported signal
number.
RELATED INFORMATION
Functions: sigaction(2), sigaddset(3), sigdelset(3), sigemptyset(3), sigfillset(3), sigproc-
mask(2), sigsuspend(2).
Files: signal(4).
STANDARDS CONFORMANCE
The POSIX standards leave some features to the implementing vendor to define. The following
features are affected in the HP implementation:
• Use of the sigismember() function on a signal set that has not been properly initialized
causes undefined results.
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