int sigwaitinfo(const sigset_t * set , siginfo_t * info ); int sigtimedwait(const sigset_t * set , siginfo_t * info , const struct timespec * timeout );

DESCRIPTION

The function sigwaitinfo() selects the pending signal from the set specified by set . Should any of multiple pending signals in the range SIGRTMIN to SIGRTMAX be selected, it will 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 is pending at the time of the call, the calling thread is suspended until one or more signals in become pending or until it is interrupted by an unblocked, caught signal. The function sigwaitinfo() behaves the same as the sigwait() function if the argument is NULL. If the argument is non-NULL, the sigwaitinfo() function behaves the same as sigwait, () except that the selected signal number is stored in the si_signo member, and the cause of the signal is stored in the si_code member. If any value is queued to the selected signal, the first such queued value is dequeued and, if the argument is non-NULL, the value is stored in the si_value member of info . The system resource used to queue the signal will be released and made available to queue other signals. If no value is queued, the content of the si_value member is undefined. If no further signals are queued for the selected signal, the pending indication for that signal will be reset. The function sigtimedwait() behaves the same as sigwaitinfo() except that if none of the signals specified by 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 are pending, then sigtimedwait() returns immediately with an error. timeout is the NULL pointer, the behaviour is unspecified.

RETURN VALUE

Upon successful completion (that is, one of the signals specified by is pending or is generated) sigwaitinfo() sigtimedwait() will return the selected signal number. Otherwise, the function returns a value of -1 and sets errno to indicate the error.

ERRORS

sigwaitinfo() sigtimedwait() functions will fail if:

[ENOSYS]

The functions sigwaitinfo() sigtimedwait() are not supported by this implementation. sigtimedwait() function will also fail if:

[EAGAIN]

No signal specified by was generated within the specified timeout period. sigwaitinfo() sigtimedwait() functions may fail if:

[EINTR]

The wait was interrupted by an unblocked, caught signal. It will be documented in system documentation whether this error will cause these functions to fail. <time.h> .

DERIVATION

Derived from the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995) and the POSIX Threads Extension (1003.1c-1995)