pthread_sigmask

Autres langues

Langue: en

Version: 2009-01-25 (fedora - 05/07/09)

Section: 3 (Bibliothèques de fonctions)

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.

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 = (sigset_t *) 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 SIGINT; 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

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