sigemptyset(2)                      CLIX                      sigemptyset(2)



  NAME

    sigemptyset, sigfillset, sigaddset, sigdelset, sigismember - Creates and
    manipulates signal masks

  LIBRARY

    Standard C Library (libc.a)

  SYNOPSIS

    #include <signal.h>

    int sigemptyset(
      sigset_t *set );

    int sigfillset(
      sigset_t *set );

    int sigaddset(
      sigset_t *set ,
      int signalnumber );

    int sigdelset(
      sigset_t *set ,
      int signalnumber );

    int sigismember(
      sigset_t *set ,
      int signalnumber );

  PARAMETERS

    set            Specifies the signal set.

    signalnumber   Specifies the individual signal.

  DESCRIPTION

    The sigemptyset(), sigfillset(), sigaddset(), sigdelset(), and
    sigismember() functions manipulate sets of signals.  These functions
    operate on data objects addressable by the application, not on any set of
    signals known to the system, such as the set blocked from delivery to a
    process or the set pending for a process.

    The sigemptyset() function initializes the signal set pointed to by the
    set parameter, such that all signals are excluded.  The sigfillset()
    function initializes the signal set pointed to by the set parameter, such
    that all signals are included.  A call to either sigfillset() or
    sigemptyset() should be made at least once for each object of the type
    sigset_t prior to any other use of that object.



  2/94 - Intergraph Corporation                                              1

  sigemptyset(2)                      CLIX                      sigemptyset(2)



    The sigaddset() function adds, and the sigdelset() function deletes, the
    individual signal specified by the signalnumber parameter from the signal
    set specified by the set parameter.  The sigismember() function tests
    whether the signalnumber parameter is a member of the signal set pointed
    to by the set parameter.

  EXAMPLES

    To generate and use a signal mask that blocks only the SIGINT signal from
    delivery, use the following:

    #include <signal.h>
    int return_value;
    sigset_t newset;
    sigset_t *newset_p;
     ...
    newset_p = &newset;
    sigemptyset(newset);
    sigaddset(newset, SIGINT);
    return_value = sigprocmask (SIG_SETMASK, newset_p, NULL);


  RETURN VALUES

    Upon successful completion, the sigismember() function returns a value of
    1 if the specified signal is a member of the specified set.  Otherwise, it
    returns a value of 0.  Upon successful completion, the other functions
    return a value of 0.  For all functions documented in this manpage, if an
    error is detected, a value of -1 is returned and the global variable errno
    is set to indicate the error.

  ERRORS

    The sigfillset(), sigdelset(), sigismember(), and sigaddset() functions
    fail if the following is true:

    [EINVAL]   The value of the signalnumber parameter is not a valid signal
               number.

  RELATED INFORMATION

    Functions:  sigprocmask(2), sigsuspend(2), sigaction(2), signal(2)












  2                                              Intergraph Corporation - 2/94