| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON | The Linux Programming Interface |
SIGPROCMASK(2) Linux Programmer's Manual SIGPROCMASK(2)
sigprocmask - examine and change blocked signals
#include <signal.h>
int sigprocmask(int how, const sigset_t *set, sigset_t *oldset);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sigprocmask(): _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_SOURCE
sigprocmask() is used to fetch and/or change the signal mask of the
calling thread. The signal mask is the set of signals whose delivery
is currently blocked for the caller (see also signal(7) for more
details).
The behavior of the call is dependent on the value of how, as
follows.
SIG_BLOCK
The set of blocked signals is the union of the current set and
the set argument.
SIG_UNBLOCK
The signals in set are removed from the current set of blocked
signals. It is permissible to attempt to unblock a signal
which is not blocked.
SIG_SETMASK
The set of blocked signals is set to the argument set.
If oldset is non-NULL, the previous value of the signal mask is
stored in oldset.
If set is NULL, then the signal mask is unchanged (i.e., how is
ignored), but the current value of the signal mask is nevertheless
returned in oldset (if it is not NULL).
The use of sigprocmask() is unspecified in a multithreaded process;
see pthread_sigmask(3).
sigprocmask() returns 0 on success and -1 on error.
EFAULT the set or oldset argument points outside the process's
allocated address space.
EINVAL The value specified in how was invalid.
POSIX.1-2001.
It is not possible to block SIGKILL or SIGSTOP. Attempts to do so
are silently ignored.
Each of the threads in a process has its own signal mask.
A child created via fork(2) inherits a copy of its parent's signal
mask; the signal mask is preserved across execve(2).
If SIGBUS, SIGFPE, SIGILL, or SIGSEGV are generated while they are
blocked, the result is undefined, unless the signal was generated by
kill(2), sigqueue(3), or raise(3).
See sigsetops(3) for details on manipulating signal sets.
kill(2), pause(2), sigaction(2), signal(2), sigpending(2),
sigsuspend(2), pthread_sigmask(3), sigqueue(3), sigsetops(3),
signal(7)
This page is part of release 3.51 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2012-04-15 SIGPROCMASK(2)
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