sigwaitinfo.2: Note treatment of signals used internally by NPTL

[thirdparty/man-pages.git] / man3 / sigwait.3

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.TH SIGWAIT 3 2015-03-02 "Linux" "Linux Programmer's Manual"
.SH NAME
sigwait \- wait for a signal
.SH SYNOPSIS
.nf
.B #include <signal.h>

.BI " int sigwait(const sigset_t *" set ", int *" sig );
.fi
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
.ad l
.BR sigwait ():
_POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _POSIX_SOURCE
.ad b
.SH DESCRIPTION
The
.BR sigwait ()
function suspends execution of the calling thread until
one of the signals specified in the signal set
.IR set
becomes pending.
The function accepts the signal
(removes it from the pending list of signals),
and returns the signal number in
.IR sig .

The operation of
.BR sigwait ()
is the same as
.BR sigwaitinfo (2),
except that:
.IP * 2
.BR sigwait ()
returns only the signal number, rather than a
.I siginfo_t
structure describing the signal.
.IP *
The return values of the two functions are different.
.SH RETURN VALUE
On success,
.BR sigwait ()
returns 0.
On error, it returns a positive error number (listed in ERRORS).
.SH ERRORS
.TP
.B EINVAL
.\" Does not occur for glibc.
.I set
contains an invalid signal number.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR sigwait ()
T}	Thread safety	MT-Safe
.TE
.SH CONFORMING TO
POSIX.1-2001.
.SH NOTES
.BR sigwait ()
is implemented using
.BR sigtimedwait (2).
.SH EXAMPLE
See
.BR pthread_sigmask (3).
.SH SEE ALSO
.BR sigaction (2),
.BR signalfd (2),
.BR sigpending (2),
.BR sigsuspend (2),
.BR sigwaitinfo (2),
.BR sigsetops (3),
.BR signal (7)