table of contents
|SIGTIMEDWAIT(2)||System Calls Manual||SIGTIMEDWAIT(2)|
wait for queued signals (REALTIME)
LIBRARY¶Standard C Library (libc, -lc)
sigtimedwait(const sigset_t *restrict set, siginfo_t *restrict info, const struct timespec *restrict timeout); int
sigwaitinfo(const sigset_t * restrict set, siginfo_t * restrict info);
sigtimedwait() system call is equivalent to
sigwaitinfo() except that if none of the signals specified by set are pending,
sigtimedwait() waits for the time interval specified in the timespec structure referenced by timeout. If the timespec structure pointed to by timeout is zero-valued and if none of the signals specified by set are pending, then
sigtimedwait() returns immediately with an error. If timeout is the
NULLpointer, the behavior is unspecified.
CLOCK_MONOTONICclock is used to measure the time interval specified by the timeout argument. The
sigwaitinfo() system call selects the pending signal from the set specified by set. Should any of multiple pending signals in the range
SIGRTMAXbe selected, it shall be the lowest numbered one. The selection order between realtime and non-realtime signals, or between multiple pending non-realtime signals, is unspecified. If no signal in set is pending at the time of the call, the calling thread is suspended until one or more signals in set become pending or until it is interrupted by an unblocked, caught signal. The
sigwaitinfo() system call is equivalent to the
sigwait() system call if the info argument is
NULL. If the info argument is non-
sigwaitinfo() function is equivalent to
sigwait(), except that the selected signal number shall be stored in the si_signo member, and the cause of the signal shall be stored in the si_code member. Besides this, the
sigtimedwait() system calls may return
EINTRif interrupted by signal, which is not allowed for the
sigwait() function. If any value is queued to the selected signal, the first such queued value is dequeued and, if the info argument is non-
NULL, the value is stored in the si_value member of info. The system resource used to queue the signal is released and returned to the system for other use. If no value is queued, the content of the si_value member is zero-valued. If no further signals are queued for the selected signal, the pending indication for that signal is reset.
RETURN VALUES¶Upon successful completion (that is, one of the signals specified by set is pending or is generated)
sigtimedwait() return the selected signal number. Otherwise, the functions return a value of -1 and set the global variable errno to indicate the error.
sigtimedwait() system call will fail if:
- No signal specified by set was generated within the specified timeout period.
sigwaitinfo() system calls fail if:
- The wait was interrupted by an unblocked, caught signal.
sigtimedwait() system call may also fail if:
- The timeout argument specified a tv_nsec value less than zero or greater than or equal to 1000 million. Kernel only checks for this error if no signal is pending in set and it is necessary to wait.
SEE ALSO¶sigaction(2), sigpending(2), sigqueue(2), sigsuspend(2), sigwait(2), pause(3), pthread_sigmask(3), siginfo(3)
sigwaitinfo() system calls conform to ISO/IEC 9945-1:1996 (“POSIX.1”).
|September 27, 2012||Debian|