PTHREAD_SIGMASK
PTHREAD_SIGMASK
NAMESYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
CONFORMING TO
NOTES
EXAMPLE
SEE ALSO
COLOPHON
NAME
pthread_sigmask − examine and change mask of blocked signals
SYNOPSIS
#include <signal.h>
int pthread_sigmask(int how, const sigset_t *set, sigset_t *oldset);
Compile and link with −pthread.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
pthread_sigmask():
_POSIX_C_SOURCE >= 199506L || _XOPEN_SOURCE >= 500
DESCRIPTION
The pthread_sigmask() function is just like sigprocmask(2), with the difference that its use in multithreaded programs is explicitly specified by POSIX.1-2001. Other differences are noted in this page.
For a description of the arguments and operation of this function, see sigprocmask(2).
RETURN VALUE
On success, pthread_sigmask() returns 0; on error, it returns an error number.
ERRORS
See sigprocmask(2).
ATTRIBUTES
Multithreading
(see pthreads(7))
The pthread_sigmask() function is thread-safe.
CONFORMING TO
POSIX.1-2001.
NOTES
A new thread inherits a copy of its creator’s signal mask.
EXAMPLE
The program below blocks some signals in the main thread, and then creates a dedicated thread to fetch those signals via sigwait(3). The following shell session demonstrates its use:
$ ./a.out
&
[1] 5423
$ kill −QUIT %1
Signal handling thread got signal 3
$ kill −USR1 %1
Signal handling thread got signal 10
$ kill −TERM %1
[1]+ Terminated ./a.out
Program
source
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
/* Simple error handling functions */
#define
handle_error_en(en, msg) \
do { errno = en; perror(msg); exit(EXIT_FAILURE); } while
(0)
static void *
sig_thread(void *arg)
{
sigset_t *set = arg;
int s, sig;
for (;;) {
s = sigwait(set, &sig);
if (s != 0)
handle_error_en(s, "sigwait");
printf("Signal handling thread got signal %d\n",
sig);
}
}
int
main(int argc, char *argv[])
{
pthread_t thread;
sigset_t set;
int s;
/* Block
SIGQUIT and SIGUSR1; other threads created by main()
will inherit a copy of the signal mask. */
sigemptyset(&set);
sigaddset(&set, SIGQUIT);
sigaddset(&set, SIGUSR1);
s = pthread_sigmask(SIG_BLOCK, &set, NULL);
if (s != 0)
handle_error_en(s, "pthread_sigmask");
s =
pthread_create(&thread, NULL, &sig_thread, (void *)
&set);
if (s != 0)
handle_error_en(s, "pthread_create");
/* Main thread
carries on to create other threads and/or do
other work */
pause(); /*
Dummy pause so we can test program */
}
SEE ALSO
sigaction(2), sigpending(2), sigprocmask(2), pthread_create(3), pthread_kill(3), sigsetops(3), pthreads(7), signal(7)
COLOPHON
This page is part of release 3.69 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 http://www.kernel.org/doc/man−pages/.
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