NAME

sigblock − block signals

SYNOPSIS

#include <signal.h>

long sigblock(long mask);

DESCRIPTION

sigblock() causes the signals specified in mask to be added to the set of signals currently being blocked from delivery.  Signal i is blocked if the i-th bit in mask is 1, as specified with the macro sigmask(i). 

It is not possible to block signals that cannot be ignored, as documented in signal(5); this restriction is silently imposed by the system.

Use sigsetmask() to set the mask absolutely (see sigsetmask(2)).

RETURN VALUE

sigblock() returns the previous set of masked signals. 

EXAMPLES

The following call to sigblock() adds the SIGUSR1 and SIGUSR2 signals to the mask of signals currently blocked for the process:

long oldmask;

oldmask = sigblock (sigmask (SIGUSR1) | sigmask (SIGUSR2));

WARNINGS

Do not use sigblock() in conjunction with the facilities described under sigset(2V).

AUTHOR

sigblock() was developed by the University of California, Berkeley. 

SEE ALSO

kill(2), sigprocmask(2), sigsetmask(2), sigvector(2). 

Hewlett-Packard Company  —  HP-UX Release 9.0: August 1992