Index for Section 3

Alphabetical listing for S

Bottom of page

sigset(3)
NAME
  sigset, sighold, sigrelse, sigignore - Compatibility interfaces for signal
  management

SYNOPSIS
  #include <sys/signal.h>

  void (*sigset(
	  int signal,
	  void (*function) (int))) (int );

  int sighold(
	  int signal );

  int sigrelse(
	  int signal );

  int sigignore(
	  int signal );

LIBRARY
  Standard C Library (libc)

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

  sigset(), sighold(), sigrelse(), sigignore():	 XSH4.2

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

PARAMETERS
  signal
      Specifies the signal.  The signal parameter can be assigned any of the
      signals defined in the signal.h header file, except SIGKILL and
      SIGSTOP.

  function
      Specifies one of four values: SIG_DFL, SIG_IGN, SIG_HOLD, or an address
      of a signal-catching function. The function() parameter is declared as
      type pointer to a function returning void.

DESCRIPTION
  The sigset(), sighold(), sigrelse(), and sigignore() functions provide
  simplified signal management.

  The sigset() function is used to modify signal dispositions.	The value of
  the function parameter determines the system signal action to be taken upon
  receipt of signal, as follows:

    ·  If function is the address of a signal-catching function, the system
       adds signal to the calling process' signal mask before executing the
       signal-catching function. When the signal-catching function returns,
       the system restores the calling process' signal mask to its state
       prior to delivery of the signal.

    ·  If function is equal to SIG_HOLD, signal is added to the calling
       process' signal mask and the disposition of signal remains unchanged.

    ·  If function is not SIG_HOLD, signal is removed from the calling
       process' signal mask.

  The sighold() function adds signal to the calling process' signal mask.

  The sigrelse() function removes signal from the calling process' signal
  mask.

  The sigignore() function sets the disposition of signal to SIG_IGN.

  The sighold() function, in conjunction with sigrelse and sigpause(), may be
  used to establish critical regions of code that require the delivery of a
  signal to be temporarily deferred.

NOTES
  These interfaces are provided for compatibility only. New programs should
  use sigaction() and sigprocmask() to control the disposition of signals.

  [Tru64 UNIX]	When compiled in the X/Open UNIX environment, calls to the
  sigset() function are internally renamed by prepending _E to the function
  name. When you are debugging a module that includes the sigset() function
  and for which _XOPEN_SOURCE_EXTENDED has been defined, use _Esigset to
  refer to the sigset() call. See standards(5) for information on when the
  _XOPEN_SOURCE_EXTENDED macro is defined.

RETURN VALUES
  Upon successful completion, the sigset() function returns the previous
  value of the system signal action for the specified signal. Otherwise, it
  returns SIG_ERR and errno is set to indicate the error.

  For the sighold(), sigrelse(), and sigignore() functions, a value of 0
  (zero) is returned upon success. Otherwise, a value of -1 is returned and
  errno is set to indicate the error.

ERRORS
  The sigset(), sighold(), sigrelse(), and sigignore() functions set errno to
  the specified values for the following conditions:

  [EINVAL]
      The signal parameter is either an illegal signal number or SIGKILL, or
      the default handling of signal cannot be changed.

SEE ALSO
  Functions: kill(2), setjmp(3), sigaction(2), sigpause(3), sigprocmask(2),
  wait(2)

  Files: signal(4)

  Standards: standards(5)

Index for Section 3

Alphabetical listing for S

Top of page