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#include <signal.h> |
sigwaitinfo() removes the delivered signal from the calling processs list of pending signals and returns the signal number as its function result. If the info argument is not NULL, then it returns a structure of type siginfo_t (see sigaction(2)) containing information about the signal.
Signals returned via sigwaitinfo() are delivered in the usual order; see signal(7) for further details.
sigtimedwait() operates in exactly the same way as sigwaitinfo() except that it has an additional argument, timeout, which enables an upper bound to be placed on the time for which the process is suspended. This argument is of the following type:
struct timespec { long tv_sec; /* seconds */ long tv_nsec; /* nanoseconds */ } |
If both fields of this structure are specified as 0, a poll is performed: sigtimedwait() returns immediately, either with information about a signal that was pending for the caller, or with an error if none of the signals in set was pending.
Tag | Description |
---|---|
EAGAIN | No signal in set was delivered within the timeout period specified to sigtimedwait(). |
EINTR | The wait was interrupted by a signal handler. (This handler was for a signal other than one of those in set.) |
EINVAL | timeout was invalid. |
POSIX leaves the meaning of a NULL value for the timeout argument of sigtimedwait() unspecified, permitting the possibility that this has the same meaning as a call to sigwaitinfo(), and indeed this is what is done on Linux.
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