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sigemptyset(3)
NAME
  sigemptyset, sigfillset, sigaddset, sigdelset, sigismember - Create and
  manipulates signal masks

SYNOPSIS
  #include <signal.h>

  int sigemptyset(
	  sigset_t *set );

  int sigfillset(
	  sigset_t *set );

  int sigaddset(
	  sigset_t *set,
	  int sig_number );

  int sigdelset(
	  sigset_t *set,
	  int sig_number );

  int sigismember(
	  sigset_t *set,
	  int sig_number );

LIBRARY
  Standard C Library (libc)

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  sigemptyset(), sigfillset(), sigaddset(), sigdelset() sigismember():	XPG4,
  XPG4-UNIX

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  set Specifies the signal set.

  sig_number
      Specifies the individual signal.

DESCRIPTION
  The sigemptyset(),sigfillset(),sigaddset()sigdelset() and sigismember()
  functions manipulate sets of signals. These functions operate on data
  objects that can be addressed 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 the sigfillset() or sigemptyset()
  function must be made at least once for each object of the type sigset_t
  prior to any other use of that object.

  The sigaddset() and sigdelset() functions respectively add and delete the
  individual signal specified by the sig_number parameter from the signal set
  specified by the set parameter. The sigismember() function tests whether
  the sig_number parameter is a member of the signal set pointed to by the
  set parameter.

RETURN VALUES
  Upon successful completion, the sigismember() function returns a value of 1
  if the specified signal is a member of the specified set, or a value of 0
  (zero) if it is not. Upon successful completion, the other functions return
  a value of 0. For all the preceding functions, if an error is detected, a
  value of -1 is returned and errno is set to indicate the error.

ERRORS
  The sigfillset(), sigdelset(), sigismember(), and sigaddset() functions set
  errno to the specified values for the following conditions:

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

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

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

SEE ALSO
  Functions: sigaction(2), sigprocmask(2), sigsuspend(2), sigvec(2)

  Files: signal(4)

  Standards: standards(5)

Index for Section 3

Alphabetical listing for S

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