NAME

       sigismember - test for a signal in a signal set

SYNOPSIS

       #include <signal.h>

       int sigismember(const sigset_t *set, int signo);

DESCRIPTION

       The sigismember() function shall test whether the signal specified by signo is a member of
       the set pointed to by set.

       Applications should call either sigemptyset() or  sigfillset()  at  least  once  for  each
       object  of  type  sigset_t prior to any other use of that object. If such an object is not
       initialized  in  this  way,  but  is  nonetheless  supplied  as  an  argument  to  any  of
       pthread_sigmask(),  sigaction(),  sigaddset(),  sigdelset(),  sigismember(), sigpending(),
       sigprocmask(), sigsuspend(), sigtimedwait(), sigwait(), or sigwaitinfo(), the results  are
       undefined.

RETURN VALUE

       Upon  successful  completion,  sigismember()  shall  return 1 if the specified signal is a
       member of the specified set, or 0 if it is not. Otherwise, it  shall  return  -1  and  set
       errno to indicate the error.

ERRORS

       The sigismember() function may fail if:

       EINVAL The  signo  argument  is  not  a  valid  signal number, or is an unsupported signal
              number.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       Signal Concepts , sigaction() , sigaddset() , sigdelset() , sigfillset() , sigemptyset() ,
       sigpending()   ,   sigprocmask()   ,   sigsuspend()  ,  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, <signal.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1,  2003  Edition,  Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  by
       the  Institute  of  Electrical  and  Electronics Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .