perlquestion sierrathedog04 Last January I posted <a href="http://www.perlmonks.org/index.pl?node_id=54322&lastnode_id=6364"> a question on how to force Perl to check at compile time that the subroutines I call exist</a>. <p> The extremely wise Tye advised to "sort your subroutines in reverse topological order (so subroutines are declared before you use them), then call all your subroutines using barewords." <p> Recently I was using CGI.pm, and I made the mistake of properly spelling the word "referrer()" instead spelling it "referer()" as CGI.pm demands. The script compiled fine and gave only run-time errors telling me that referrer() does not exist. <p>Since I did not write CGI.pm I cannot sort it in topological order. How can I force Perl to check that the functions I call in the CPAN modules exist?