sigpending(S)

sigpending -- examine signals that are blocked and pending

Synopsis

   #include <signal.h>
   
   int sigpending(sigset_t *set);

Description

The sigpending function retrieves those signals that have been sent to the calling process but are being blocked from delivery by the calling process's signal mask. The signals are stored in the space pointed to by the argument set.

Return values

On success, sigpending returns 0. On failure, sigpending returns -1 and sets errno to identify the error.

Errors

In the following conditions, sigpending fails and sets errno to:

EFAULT: The set argument points outside the process's allocated address space.

References

sigaction(S), sigprocmask(S), sigsetops(S)

Notices

Considerations for threads programming

The set returned is the union of

Signals pending to the calling thread but blocked by that thread's signal mask.
Signals pending to the process but blocked by every currently running thread in the process.

In general, the status from sigpending is only advisory. A signal pending to the containing process might be delivered to a sibling thread (if any become eligible) after the return of this system call. See signal(M) for further details.

Considerations for lightweight processes

In terms of LWPs, the set returned is the union of

Signals pending to the calling LWP but blocked by that LWP's signal mask.
Signals pending to the process but blocked by every LWP contained in the process.