sigsetops(3)               DG/UX 4.30                sigsetops(3)



     NAME
          sigsetops: sigemptyset, sigfillset, sigaddset, sigdelset,
          sigismember - Manipulate signal sets.

     FUNCTIONS
          sigemptyset(), sigfillset(), sigaddset(), sigdelset(),
          sigismember()

     SYNOPSIS
          #include <signal.h>
          int sigemptyset (set)
          sigset_t *set;

          int sigfillset (set)
          sigset_t *set;

          int sigaddset (set, signo)
          sigset_t *set;
          int signo;

          int sigdelset (set, signo)
          sigset_t *set;
          int signo;

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

     DESCRIPTION
          The sigsetops primitives manipulate sets of signals.  They
          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 (see <signal.h>).

          The sigemptyset() function initializes the signal set
          pointed to by the argument set, such that all signals
          defined in this standard are excluded.

          The sigfillset() function initializes the signal set pointed
          to by the argument set, such that all signals defined in
          this standard are included.

          Applications shall 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 the sigaddset(), sigdelset(),
          sigismember(), sigaction(), sigprocmask(), sigpending(), or
          sigsuspend() functions, the results are undefined.

          The sigaddset() and sigdelset() functions respectively add



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     sigsetops(3)               DG/UX 4.30                sigsetops(3)



          and delete the individual signal specified by the value of
          the argument signo from the signal set pointed to by the
          argument set.

          The sigismember() function tests whether the signal
          specified by the value of the argument signo is a member of
          the set pointed to by the argument set.

     RETURNS
          Upon successful completion, the sigismember() function
          returns a value of one if the specified signal is a member
          of the specified set, or a value of zero if it is not.  Upon
          successful completion, the other functions return a value of
          zero.  For all of the above functions, if an error is
          detected, a value of -1 is returned and errno is set to
          indicate the error.

     ERRORS
          For each of the following conditions, if the condition is
          detected, the sigaddset(), sigdelset(), and sigismember()
          functions shall return -1 and set errno to the corresponding
          value:

     [EINVAL]
               The value of the signo argument is an invalid or
               unsupported signal number.

     SEE ALSO
          sigaction(2), <signal.h>, sigpending(2) sigprocmask(2),
          sigsuspend(2)

     COPYRIGHTS
          Portions of this text are reprinted from IEEE Std 1003.1-
          1988, Portable Operating System Interface for Computer
          Environment, copyright © 1988 by the Institute of Electrical
          and Electronics Engineers, Inc., with the permission of the
          IEEE Standards Department.  To purchase IEEE Standards, call
          800/678-IEEE.

          In the event of a discrepancy between the electronic and the
          original printed version, the original version takes
          precedence.













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