Just for kicks here's my attempt at handling fully qualified names (including archaic forms), prototypes, and attributes.

#! perl -slw
use strict;
use re 'eval';

my $re_sub = qr[
    sub\s+
    (
        (?: (\w+)? (?: :: | ' ) )*
        \w+ \s*
    )
    (?{ $name = $^N })
    (
        (?: \( [&$@\\; ]+ \) )? \s*
    )
    (?{ $prototype = $^N || '' })
    (
        (?: : \s* \w+ (?: \( .+? \) )? \s* )*
    )
    (?{ $attributes = $^N || '' })
    \{
]x;

BEGIN{ @ARGV = map{ glob } @ARGV if $^O eq 'MSWin32'; }

our( $name, $prototype, $attributes );
local $/ = undef;
while( <> ) {
    tr[\n][];
    s[\s+][ ]g;
    printf "%-40s : Name: %-20s\tPrototype: %10s\n\tAttributes : %s\n"
+,
        $ARGV, $name, $prototype, $attributes
        while m[$re_sub]g;
}
[download]

It's quite interesting to run this against the files in your libpath.

Of course this doesn't respect comments or pod boundaries.