sigpending(2) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | NOTES | BUGS | SEE ALSO | COLOPHON

 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 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 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         top

 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         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. 

SEE ALSO         top

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

COLOPHON         top

 This page is part of the man-pages (Linux kernel and C library user-space interface documentation) project. Information about the project can be found at ⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report for this manual page, see ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩. This page was obtained from the tarball man-pages-6.15.tar.gz fetched from ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on 2025-08-11. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org Linux man-pages 6.15 2025-05-17 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)