NAME

       sigpending, rt_sigpending - examine pending signals

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <signal.h>

       int sigpending(sigset_t *set);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       sigpending():
           _POSIX_C_SOURCE

DESCRIPTION

       sigpending()  returns  the  set of signals that are pending for delivery to the calling thread (i.e., the
       signals which have been raised while blocked).  The mask of pending signals is returned in set.

RETURN VALUE

       sigpending() returns 0 on success.  On failure, -1 is returned and errno is set to indicate the error.

ERRORS

       EFAULT set points to memory which is not a valid part of the process address space.

STANDARDS

       POSIX.1-2008.

HISTORY

       POSIX.1-2001.

   C library/kernel differences
       The original Linux system call was named sigpending().  However, with the addition of  real-time  signals
       in  Linux  2.2,  the fixed-size, 32-bit sigset_t argument supported by that system call was no longer fit
       for purpose.  Consequently, a new system call, rt_sigpending(), was added to support an enlarged sigset_t
       type.  The new system call takes a second argument, size_t sigsetsize, which specifies the size in  bytes
       of  the  signal  set  in  set.   The  glibc  sigpending()  wrapper  function hides these details from us,
       transparently calling rt_sigpending() when the kernel provides it.

NOTES

       See sigsetops(3) for details on manipulating signal sets.

       If a signal is both blocked and has a disposition of "ignored", it is not added to the  mask  of  pending
       signals when generated.

       The  set  of  signals that is pending for a thread is the union of the set of signals that is pending for
       that thread and the set of signals that is pending for the process as a whole; see signal(7).

       A child created via fork(2) initially has an  empty  pending  signal  set;  the  pending  signal  set  is
       preserved across an execve(2).

BUGS

       Up to and including glibc 2.2.1, there is a bug in the wrapper function for sigpending() which means that
       information about pending real-time signals is not correctly returned.

SEE ALSO

       kill(2), sigaction(2), signal(2), sigprocmask(2), sigsuspend(2), sigsetops(3), signal(7)

Linux man-pages 6.7                                2023-10-31                                      sigpending(2)