NAME

sigblock − block signals

SYNOPSIS

#include <signal.h>

long sigblock(mask);
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, as specified with the macro sigmask(i), is a 1. 

It is not possible to block those signals which cannot be ignored, as documented in signal(2); this restriction is silently imposed by the system.

Sigsetmask(2) can be used to set the mask absolutely.

RETURN VALUE

The previous set of masked signals is returned. 

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));

DEPENDENCIES

Series 500, 800
The macro sigmask(i) is currently not supported.  See sigvector(2) for its expansion. 

AUTHOR

Sigblock was developed by the University of California, Berkeley California, Computer Science Division, Department of Electrical Engineering and Computer Science. 

SEE ALSO

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

Hewlett-Packard Company  —  Version B.1,  May 11, 2021