# sigset(3)

    NAME
         sigset, sigaddset,  sigdelset,  sigemptyset,  sigfillset,  sigismember  -
         manipulate signal sets

    SYNOPSIS
         #include <signal.h>

         int sigaddset(sigset_t *set, int sig)
         int sigdelset(sigset_t *set, int sig)
         int sigemptyset(sigset_t *set)
         int sigfillset(sigset_t *set)
         int sigismember(const sigset_t *set, int sig)

    DESCRIPTION
         The  system  calls  that  handle  signals,  such  as   sigaction(2)   and
         sigprocmask(2)  use  sets  of  signals  to  keep  a  process  from  being
         interrupted by those signals  while  executing  a  signal  handler  or  a
         critical  code  segment.   These  signal  sets  are  manipulated  by  the
         following functions:

         int sigaddset(sigset_t *set, int sig)
              Add signal sig to the signal set referenced by set.

         int sigdelset(sigset_t *set, int sig)
              Remove signal sig from the signal set referenced by set.

         int sigemptyset(sigset_t *set)
              Initialize the signal set referenced by set to an empty set.

         int sigfillset(sigset_t *set)
              Initialize the signal set referenced by set to an full set, i.e. all
              signals are in the set.

         int sigismember(const sigset_t *set, int sig)
              Return 1 if the signal sig is present in the set referenced by  set,
              0 otherwise.

    SEE ALSO
         sigaction(2), sigpending(2), sigprocmask(2), sigsuspend(2).

    DIAGNOSTICS
         All functions  except  sigismember  return  0  on  success.   Sigismember
         returns  0 or 1 on success.  They return -1 with error code EINVAL for an
         invalid signal number.  (They do not use EFAULT for a  bad  set  address,
         but will simply cause a segmentation violation.)

    AUTHOR
         Kees J. Bot (kjb@cs.vu.nl)