The BEGIN block is executed at parse time, but only when the parser finds it - it works top-down so it finds the prototype definition after it has parsed the call, when it is too late.

There is an alternative, which uses a similar technique to C, and that is to declare the prototype before the call. For example:
use warnings;
use strict;

mysub('duff');   

sub mysub() {
        print "mysub\n"
}

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Gives:
main::mysub() called too early to check prototype

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But we add the declaration:
use warnings;
use strict;

sub mysub();    # mysub declaration

mysub('duff');

sub mysub() {
        print "mysub\n"
}

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and we get:
Too many arguments for main::mysub

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as expected.

In reply to Re: BEGIN block and prototyped subroutines by cdarke
in thread BEGIN block and prototyped subroutines by hangon

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