That's because you are doing it wrong. Carp is your friend: 
use warnings; 
use strict; 
use Carp;

func(one => 'uno', two => 'dos', three => ); 

sub func { 
    croak "wrong number of arguments for func(); has to be even" if sc
+alar(@_) % 2;
    my %args = @_; 
    print "func: one translates to $args{one} \n"; 
}

[download]
prints 
wrong number of arguments for func(); has to be even at a.pl line 8
    main::func('one', 'uno', 'two', 'dos', 'three') called at a.pl lin
+e 5

[download]

In reply to Re^2: Preferred technique for named subroutine parameters? by akho
in thread Preferred technique for named subroutine parameters? by Anonymous Monk

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