my	$TRUE	= 1;
my	$FALSE	= 0;
     [...]
my $EofFlag = $FALSE;
while(!$EofFlag)
{
     [...]
	my $cmtseq_cnt = read(perlIN,$cmtseq,5);
	if ($cmtseq_cnt < 5)
	{
		$EofFlag = $TRUE;	# Redundant, given what we do next, but here for example
		last;
	}
}