in reply to Detect undefined subroutines

There doesn't appear to be any way to do what you want. The trouble being that Perl's subs are dynamic, so it is completely fair to have a sub that is created on the fly, and only exists when the program is running.

This is, after all, what happens when you import a module.

A quick browse of CPAN didn't show up any module that would do run-time checks for functions to exist, so it sounds like you have 'an opportunity, rather than a problem'.

I didn't believe in evil until I dated it.