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PTHREAD_SIGMASK(3) - Linux manual page online | Library functions

Examine and change mask of blocked signals.

PTHREAD_SIGMASK(3) Linux Programmer's Manual PTHREAD_SIGMASK(3)


pthread_sigmask - examine and change mask of blocked signals


#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


The pthread_sigmask() function is just like sigprocmask(2), with the difference that its use in multithreaded programs is explicitly specified by POSIX.1. Other differences are noted in this page. For a description of the arguments and operation of this function, see sigprocmask(2).


On success, pthread_sigmask() returns 0; on error, it returns an error number.


See sigprocmask(2).


For an explanation of the terms used in this section, see attributes(7). ┌──────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├──────────────────┼───────────────┼─────────┤ │pthread_sigmask() │ Thread safety │ MT-Safe │ └──────────────────┴───────────────┴─────────┘


POSIX.1-2001, POSIX.1-2008.


A new thread inherits a copy of its creator's signal mask. The glibc pthread_sigmask() function silently ignores attempts to block the two real-time signals that are used internally by the NPTL threading implementation. See nptl(7) for details.


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 */ }


sigaction(2), sigpending(2), sigprocmask(2), pthread_create(3), pthread_kill(3), sigse‐ tops(3), pthreads(7), signal(7)


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Linux 2017-09-15 PTHREAD_SIGMASK(3)
This manual Reference Other manuals
pthread_sigmask(3) referred by nptl(7) | pth(3) | pthread_create(3) | pthread_kill(3) | pthread_sigqueue(3) | pthreads(7) | sigaction(2freebsd) | signal(7) | signal-safety(7) | sigprocmask(2freebsd) | sigqueue(2freebsd) | sigtimedwait(2freebsd) | sigwait(2freebsd) | sigwait(3) | sigwaitinfo(2freebsd)
refer to attributes(7) | feature_test_macros(7) | nptl(7) | pthread_create(3) | pthread_kill(3) | pthreads(7) | sigaction(2) | signal(7) | sigpending(2) | sigprocmask(2) | sigwait(3)
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