I have a problem that is very frustrating and should not happen
according to the documentation.
I have a perl spam filtering program that either drops the email
altogether if it is a suspected spam, or lets it proceed into the
spool file if the email is legitimate.

My .procmailrc file is very simple and consists of the following:

LOGFILE=log.procmail
VERBOSE=yeah

:0 fr: perl.lock
 | /usr/bin/perl /usr/local/mailer/checkmail.pl


The problem arises when I filter out an email. Even though my perl
program produces no output under these circumstances, procmail
insists on inserting a blank line into the spool file (notwithstanding
the fact that I have the 'r' flag set). This causes the spool file
to be unreadable if the blank line is the first line of the file.
This happens if the user pops all of his/her email (removing the mail from
the server) and the next email to arrive is a spam blocked email (resulting
in a blank first line of the spool file). Am I correct in assuming that the
'r' flag should stop the extra line from going into the spool file?
Is there a workaround other than rewriting some of the procmail code?