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Diffstat (limited to 'man3/pthread_sigmask.3')
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diff --git a/man3/pthread_sigmask.3 b/man3/pthread_sigmask.3 new file mode 100644 index 0000000..724f1e9 --- /dev/null +++ b/man3/pthread_sigmask.3 @@ -0,0 +1,163 @@ +'\" t +.\" Copyright (c) 2009 Linux Foundation, written by Michael Kerrisk +.\" <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH pthread_sigmask 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +pthread_sigmask \- examine and change mask of blocked signals +.SH LIBRARY +POSIX threads library +.RI ( libpthread ", " \-lpthread ) +.SH SYNOPSIS +.nf +.B #include <signal.h> +.PP +.BI "int pthread_sigmask(int " how ", const sigset_t *" set \ +", sigset_t *" oldset ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR pthread_sigmask (): +.nf + _POSIX_C_SOURCE >= 199506L || _XOPEN_SOURCE >= 500 +.fi +.SH DESCRIPTION +The +.BR pthread_sigmask () +function is just like +.BR sigprocmask (2), +with the difference that its use in multithreaded programs +is explicitly specified by POSIX.1. +Other differences are noted in this page. +.PP +For a description of the arguments and operation of this function, see +.BR sigprocmask (2). +.SH RETURN VALUE +On success, +.BR pthread_sigmask () +returns 0; +on error, it returns an error number. +.SH ERRORS +See +.BR sigprocmask (2). +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR pthread_sigmask () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +POSIX.1-2008. +.SH HISTORY +POSIX.1-2001. +.SH NOTES +A new thread inherits a copy of its creator's signal mask. +.PP +The glibc +.BR pthread_sigmask () +function silently ignores attempts to block the two real-time signals that +are used internally by the NPTL threading implementation. +See +.BR nptl (7) +for details. +.SH EXAMPLES +The program below blocks some signals in the main thread, +and then creates a dedicated thread to fetch those signals via +.BR sigwait (3). +The following shell session demonstrates its use: +.PP +.in +4n +.EX +.RB "$" " ./a.out &" +[1] 5423 +.RB "$" " kill \-QUIT %1" +Signal handling thread got signal 3 +.RB "$" " kill \-USR1 %1" +Signal handling thread got signal 10 +.RB "$" " kill \-TERM %1" +[1]+ Terminated ./a.out +.EE +.in +.SS Program source +\& +.\" SRC BEGIN (pthread_sigmask.c) +.EX +#include <errno.h> +#include <pthread.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +\& +/* Simple error handling functions */ +\& +#define handle_error_en(en, msg) \e + 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\en", sig); + } +} +\& +int +main(void) +{ + 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, &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 */ +} +.EE +.\" SRC END +.SH SEE ALSO +.BR sigaction (2), +.BR sigpending (2), +.BR sigprocmask (2), +.BR pthread_attr_setsigmask_np (3), +.BR pthread_create (3), +.BR pthread_kill (3), +.BR sigsetops (3), +.BR pthreads (7), +.BR signal (7) |