SIGPENDING(2)               Linux Programmer's Manual              SIGPENDING(2)

       sigpending, rt_sigpending - examine pending signals

       #include <signal.h>

       int sigpending(sigset_t *set);

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


       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.

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

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

       POSIX.1-2001, POSIX.1-2008.

       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).

   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.

       In versions of glibc up to and including 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.

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

       This page is part of release 5.13 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

Linux                              2021-03-22                      SIGPENDING(2)