osf1 man page for sigblock

sigblock(2)							System Calls Manual						       sigblock(2)

NAME
       sigblock - Provides a compatibility interface to the sigprocmask function

LIBRARY
       Standard C Library (libc.a)

SYNOPSIS
       int sigblock( int mask );

PARAMETERS
       Specifies the signals to be added to the set of signals currently being blocked from delivery.

DESCRIPTION
       The  sigblock()	function causes the signals specified by the mask parameter to be added to the set of signals currently being blocked from
       delivery. The signals are blocked from delivery by logically ORing the mask parameter into the signal mask of the  process.   Signal  i	is
       blocked if the i-th bit in the mask parameter is a value of 1. Only signals with values 1-31 can be masked with the sigblock() function.

NOTES
       It is not possible to block SIGKILL. The system provides no indication of this restriction.

       The sigblock() function is provided for compatibility to other UNIX systems. Its function is a subset of the sigprocmask() function.

RETURN VALUES
       On completion, the previous set of masked signals is returned.

RELATED INFORMATION
       Functions: kill(2), sigaction(2), sigpause(3), sigprocmask(2), sigsuspend(2), sigvec(2) delim off

																       sigblock(2)