Manual Reference Pages  - PTHREAD_SIGMASK (3)

NAME

pthread_sigmask - examine and change mask of blocked signals

CONTENTS

Synopsis
Description
Return Value
Errors
Conforming To
Notes
Example
     Program source
See Also
Colophon

SYNOPSIS


#include <signal.h> 

int pthread_sigmask(int how, const sigset_t *set ", sigset_t *" oldset );

Compile and link with -pthread.

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).

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 3.44 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 PTHREAD_SIGMASK (3) 2012-08-03
blog comments powered by Disqus