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

NAME
       pthreadsigmask - examine and change mask of blocked signals

SYNOPSIS
       #include 

       int pthreadsigmask(int how, const sigsett *set, sigsett *oldset);

       Compile and link with -pthread.

DESCRIPTION
       The  pthreadsigmask()  function  is just like sigprocmask(2), with the
       difference that its use in multithreaded programs is explicitly  speci‐
       fied 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, pthreadsigmask() returns 0; on error, it returns an  error
       number.

ERRORS
       See sigprocmask(2).

ATTRIBUTES
       For   an   explanation   of   the  terms  used  in  this  section,  see
       attributes(7).

       ┌──────────────────┬───────────────┬─────────┐
       │Interface         │ Attribute     │ Value   │
       ├──────────────────┼───────────────┼─────────┤
       │pthreadsigmask() │ Thread safety │ MT-Safe │
       └──────────────────┴───────────────┴─────────┘
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 cre‐
       ates  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 
       #include 
       #include 
       #include 
       #include 
       #include 

       /* Simple error handling functions */

       #define handleerroren(en, msg) \
               do { errno = en; perror(msg); exit(EXITFAILURE); } while (0)

       static void *
       sigthread(void *arg)
       {
           sigsett *set = arg;
           int s, sig;

           for (;;) {
               s = sigwait(set, &sig);
               if (s != 0)
                   handleerroren(s, "sigwait");
               printf("Signal handling thread got signal %d\n", sig);
           }
       }

       int
       main(int argc, char *argv[])
       {
           pthreadt thread;
           sigsett 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 = pthreadsigmask(SIGBLOCK, &set, NULL);
           if (s != 0)
               handleerroren(s, "pthreadsigmask");

           s = pthreadcreate(&thread, NULL, &sigthread, (void *) &set);
           if (s != 0)
               handleerroren(s, "pthreadcreate");

           /* 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),    pthreadcreate(3),
       pthreadkill(3), sigsetops(3), pthreads(7), signal(7)

COLOPHON
       This  page  is  part of release 3.53 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                             2012-08-03                PTHREADSIGMASK(3)