Assuming that libraries are being created, how does one take advantage of prototypes in the case where subroutines are spread across files? Given the following code: 
#!/usr/bin/perl

use strict;

require 'include.pl';

sub localAdd($$);
#sub remoteAdd($$);    # Is this required?

my $i;

$i = localAdd 1, 2;
#$i = localAdd 1, 2, 3;    # error: "Too many arguments for main:local
+Add at test.pl line 9, near "3;"
print "i = $i\n";

#$i = remoteAdd 1, 2;      # error: "Number found where operator expec
+ted at test.pl line 15, near "remoteAdd 1" (Do you need to predeclare
+ remoteAdd?)
#$i = remoteAdd 1, 2, 3;
#print "i = $i\n";

$i = remoteAdd(1, 2);
$i = remoteAdd(1, 2, 3);   # prototype in include.pl is not honored
print "i = $i\n";

sub localAdd($$) {
    my ($i, $j) = @_;
    return $i + $j;
}

[download]
where include.pl contains the following: 
sub remoteAdd($$);    # This appears to have no effect across files...

sub remoteAdd($$) {
#   die "incorrect #arguments in remoteAdd" unless @_ == 2;
    my ($i, $j) = @_;
    return $i + $j;
}

1;

[download]
Prototypes get around expliciting checking for the number of parameters passed to a subroutine, but when subroutines are spread across multiple files, I no longer am seeing the interpreter perform this check for me. How do I get this functionality back for free?

Thanks for any insight on this issue.

In reply to subroutine prototypes effectiveness across files? by Anonymous Monk

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