sigpending(2)

1sigpending(2)                 System Calls Manual                sigpending(2)
2
3
4

NAME

6       sigpending, rt_sigpending - examine pending signals
7

LIBRARY

9       Standard C library (libc, -lc)
10

SYNOPSIS

12       #include <signal.h>
13
14       int sigpending(sigset_t *set);
15
16   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
17
18       sigpending():
19           _POSIX_C_SOURCE
20

DESCRIPTION

22       sigpending()  returns  the set of signals that are pending for delivery
23       to the calling thread (i.e., the signals which have been  raised  while
24       blocked).  The mask of pending signals is returned in set.
25

RETURN VALUE

27       sigpending()  returns 0 on success.  On failure, -1 is returned and er‐
28       rno is set to indicate the error.
29

ERRORS

31       EFAULT set points to memory which is not a valid part  of  the  process
32              address space.
33

STANDARDS

35       POSIX.1-2008.
36

HISTORY

38       POSIX.1-2001.
39
40   C library/kernel differences
41       The  original  Linux system call was named sigpending().  However, with
42       the addition of real-time signals in Linux 2.2, the fixed-size,  32-bit
43       sigset_t  argument  supported by that system call was no longer fit for
44       purpose.  Consequently, a new system call, rt_sigpending(),  was  added
45       to support an enlarged sigset_t type.  The new system call takes a sec‐
46       ond argument, size_t sigsetsize, which specifies the size in  bytes  of
47       the  signal  set in set.  The glibc sigpending() wrapper function hides
48       these details from us, transparently calling rt_sigpending()  when  the
49       kernel provides it.
50

NOTES

52       See sigsetops(3) for details on manipulating signal sets.
53
54       If  a  signal is both blocked and has a disposition of "ignored", it is
55       not added to the mask of pending signals when generated.
56
57       The set of signals that is pending for a thread is the union of the set
58       of  signals that is pending for that thread and the set of signals that
59       is pending for the process as a whole; see signal(7).
60
61       A child created via fork(2) initially has an empty pending signal  set;
62       the pending signal set is preserved across an execve(2).
63

BUGS

65       Up to and including glibc 2.2.1, there is a bug in the wrapper function
66       for sigpending() which means that information about  pending  real-time
67       signals is not correctly returned.
68