Why am I getting “called too early to check prototype” warnings in my Perl code?

Question

I have a Perl file like this:

use strict;
f1();

sub f3()
{ f2(); }

sub f1()
{}
sub f2()
{}

In short, f1 is called before it is d

Answer 1

You can completely avoid this issue by not using prototypes in the first place:

use strict;

f1();

sub f3 { f2() }

sub f1 {}
sub f2 {}

Don't use prototypes unless you know why you are using them:

This is all very powerful, of course, and should be used only in moderation to make the world a better place.