If you are hell-bent on doing that, and having doc-strings for your functions, the following style may be to your taste:

use vars %documentation;

sub doc($$) {
    my ($for,$doc) = @_;
    $documentation{ $for } = $doc;
};

doc('mysub1',<<'=cut');

=head2 C<< mysub1 >>

This documents mysub1. An example:

  mysub1();

=cut

sub mysub1 {
    ...
};

doc('frobnicate',<<'=cut');

=head2 C<< frobnicate >>

This documents frobnicate. An example:

  frobnicate();

=cut

sub frobnicate {
    ...
};
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You will note from history that this style never caught on.

If you adhere to a strict documentation style, you may simply parse the POD and extract the function definitions from that. Using "docstrings" and parsing the module documentation are equivalent in that sense.