sigpending(2) - Linux manual page (original) (raw)

sigpending(2) System Calls Manual sigpending(2)

NAME top

   sigpending, rt_sigpending - examine pending signals

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <signal.h>**

   **int sigpending(sigset_t ***_set_**);**

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

   **sigpending**():
       _POSIX_C_SOURCE

DESCRIPTION top

   **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 top

   **sigpending**() returns 0 on success.  On failure, -1 is returned and
   _[errno](../man3/errno.3.html)_ is set to indicate the error.

ERRORS top

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

STANDARDS top

   POSIX.1-2008.

HISTORY top

   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 sigsett 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 sigsett type. The new system call takes a second argument, sizet 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 top

   See [sigsetops(3)](../man3/sigsetops.3.html) 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)](../man7/signal.7.html).

   A child created via [fork(2)](../man2/fork.2.html) initially has an empty pending signal
   set; the pending signal set is preserved across an [execve(2)](../man2/execve.2.html).

BUGS top

   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.

COLOPHON top

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Linux man-pages 6.10 2024-07-23 sigpending(2)

Pages that refer to this page:clone(2), fork(2), sigaction(2), signal(2), sigprocmask(2), sigwaitinfo(2), syscalls(2), pthread_create(3), pthread_kill(3), pthread_sigmask(3), sigsetops(3), sigwait(3), signal(7), signal-safety(7), system_data_types(7)