SunOS/BSD Compatibility Library Functions          sigblock(3UCB)



NAME
     sigblock, sigmask, sigpause, sigsetmask - block signals

SYNOPSIS
     /usr/ucb/cc [ flag ... ] file ...
     #include 

     int sigblock(mask)
     int mask;


     int sigmask(signum)
     int signum;


     int sigpause(mask)
     int mask;


     int sigsetmask(mask)
     int mask;


DESCRIPTION
     sigblock() adds the signals specified in mask to the set  of
     signals  currently being blocked from delivery.  Signals are
     blocked if the appropriate bit in mask is  a  1;  the  macro
     sigmask  is  provided to construct the mask for a given sig-
     num. sigblock() returns the previous mask. The previous mask
     may be restored using sigsetmask().


     sigpause() assigns mask to the set  of  masked  signals  and
     then  waits  for  a  signal  to arrive; on return the set of
     masked signals is restored. mask is usually  0  to  indicate
     that  no  signals  are  now to be blocked. sigpause() always
     terminates by being interrupted, returning  -1  and  setting
     errno to EINTR.


     sigsetmask() sets the current  signal  mask  (those  signals
     that are blocked from delivery).  Signals are blocked if the
     corresponding bit in mask is a 1; the macro sigmask is  pro-
     vided to construct the mask for a given signum.


     In normal usage, a signal is blocked  using  sigblock().  To
     begin   a   critical  section,  variables  modified  on  the
     occurrence of the signal  are  examined  to  determine  that
     there is no work to be done, and the process pauses awaiting
     work by using sigpause() with  the  mask  returned  by  sig-
     block().



SunOS 5.11          Last change: 30 Oct 2007                    1






SunOS/BSD Compatibility Library Functions          sigblock(3UCB)



     It is not possible to block SIGKIL, SIGSTOP,  or   SIGCONT,
     this restriction is silently imposed by the system.

RETURN VALUES
     sigblock() and  sigsetmask()  return  the  previous  set  of
     masked  signals.  sigpause()  returns  -1  and sets errno to
     EINTR.

SEE ALSO
     cc(1B), kill(2), sigaction(2), signal(3UCB), sigvec(3UCB)

NOTES
     Use of these interfaces should be restricted to only  appli-
     cations  written  on BSD platforms.  Use of these interfaces
     with any of the system libraries or in multi-thread applica-
     tions is unsupported.







































SunOS 5.11          Last change: 30 Oct 2007                    2