NAME

sigblock − block signals

SYNOPSIS

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 is a 1 (that is, if (mask & (1L << (i-1))) != 0 ). 

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.

EXAMPLES

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

#define MASK(s)(1L << ((s)-1)) long oldmask;

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

RETURN VALUE

The previous set of masked signals is returned. 

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