pthread_sigmask(3)

1PTHREAD_SIGMASK(3)         Linux Programmer's Manual        PTHREAD_SIGMASK(3)
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NAME

6       pthread_sigmask - examine and change mask of blocked signals
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SYNOPSIS

9       #include <signal.h>
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11       int pthread_sigmask(int how, const sigset_t *set, sigset_t *oldset);
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13       Compile and link with -pthread.
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DESCRIPTION

16       The  pthread_sigmask()  function  is just like sigprocmask(2), with the
17       difference that its use in multithreaded programs is explicitly  speci‐
18       fied by POSIX.1-2001.  Other differences are noted in this page.
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20       For  a description of the arguments and operation of this function, see
21       sigprocmask(2).
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RETURN VALUE

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

28       See sigprocmask(2).
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CONFORMING TO

31       POSIX.1-2001.
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NOTES

34       A new thread inherits a copy of its creator's signal mask.
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EXAMPLE

37       The program below blocks some signals in the main thread, and then cre‐
38       ates a dedicated thread to fetch those  signals  via  sigwait(3).   The
39       following shell session demonstrates its use:
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41           $ ./a.out &
42           [1] 5423
43           $ kill -QUIT %1
44           Signal handling thread got signal 3
45           $ kill -USR1 %1
46           Signal handling thread got signal 10
47           $ kill -TERM %1
48           [1]+  Terminated              ./a.out
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50   Program source
51
52       #include <pthread.h>
53       #include <stdio.h>
54       #include <stdlib.h>
55       #include <unistd.h>
56       #include <signal.h>
57       #include <errno.h>
58
59       /* Simple error handling functions */
60
61       #define handle_error_en(en, msg) \
62               do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)
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64       static void *
65       sig_thread(void *arg)
66       {
67           sigset_t *set = arg;
68           int s, sig;
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70           for (;;) {
71               s = sigwait(set, &sig);
72               if (s != 0)
73                   handle_error_en(s, "sigwait");
74               printf("Signal handling thread got signal %d\n", sig);
75           }
76       }
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78       int
79       main(int argc, char *argv[])
80       {
81           pthread_t thread;
82           sigset_t set;
83           int s;
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85           /* Block SIGQUIT and SIGUSR1; other threads created by main()
86              will inherit a copy of the signal mask. */
87
88           sigemptyset(&set);
89           sigaddset(&set, SIGQUIT);
90           sigaddset(&set, SIGUSR1);
91           s = pthread_sigmask(SIG_BLOCK, &set, NULL);
92           if (s != 0)
93               handle_error_en(s, "pthread_sigmask");
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95           s = pthread_create(&thread, NULL, &sig_thread, (void *) &set);
96           if (s != 0)
97               handle_error_en(s, "pthread_create");
98
99           /* Main thread carries on to create other threads and/or do
100              other work */
101
102           pause();            /* Dummy pause so we can test program */
103       }
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COLOPHON

110       This page is part of release 3.53 of the Linux  man-pages  project.   A
111       description  of  the project, and information about reporting bugs, can
112       be found at http://www.kernel.org/doc/man-pages/.
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116Linux                             2012-08-03                PTHREAD_SIGMASK(3)