my $emptySigSet = POSIX::SigSet->new();
 my $oldSigSet = POSIX::SigSet->new();
 POSIX::sigprocmask( &POSIX::SIG_BLOCK, $emptySigSet, $oldSigSet );

 if ( $oldSigSet->ismember( &POSIX::SIGHUP ) ){
     print "SIGHUP is blocking.\n";
 }else {
     print "SIGHUP is not blocking.\n";
 }