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SunOS/BSD Compatibility Library Functionssigblock(3UCB)


NAME

 sigblock, sigmask, sigpause, sigsetmask - block signals

SYNOPSIS

 
/usr/ucb/cc [ flag ... ] file ...
#include <signal.h>
int sigblock(mask,
intmask;
 int sigmask( signum,
int signum;
 int sigpause(int mask,
int mask;
 int sigsetmask( mask,
int mask;

DESCRIPTION

 

sigblock, sigmask, sigpause, sigsetmask - block signals

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 signum. 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 provided 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 sigblock().

It is not possible to block SIGKILL, 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

 

kill(2), sigaction(2), signal(3UCB), sigvec(3UCB)

NOTES

 

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


SunOS 5.9Go To TopLast Changed 19 Feb 1993

 
      
      
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.