How to handle subroutine redefined errors in Perl

Question

So I have a file that in short has this problem...

#!/usr/bin/perl -w
package Foo;

use strict;
use POSIX;

...

sub remove {
  ...
}
...

and I get a get an error saying the subroutine remove has been redefined. I know the problem, there is a subroutine called remove in POSIX. However, I don't know how to handle it. How is this problem typically solved?

score 27 · Answer 1 · answered Aug 29 '10 at 03:30

27

The other way to suppress this warning is to put your subroutine redefinition inside a no warnings 'redefine' block:

{
    no warnings 'redefine';
    sub remove { ... }
}

answered Aug 29 '10 at 03:30

mob

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score 22 · Accepted Answer · answered Aug 29 '10 at 03:02

22

do this:

use POSIX ();

which will stop the export all default functionality of the POSIX module. You will then need to prefix all POSIX methods with POSIX:: such as:

POSIX::remove(filename)

for the POSIX remove function.

answered Aug 29 '10 at 03:02

ennuikiller

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Thanks. Is this conventional? – floogads Aug 29 '10 at 03:08
1

Yes, in general to avoid conflicting subroutine definitions its best to import nothing or only those subroutines you are sure will have unique names. – ennuikiller Aug 29 '10 at 03:17
6

@floogads, it's more usual to say `use POSIX qw(mkfifo modf);` where you explicitly list all the functions you want to import. That way, you don't have to use the `POSIX::` prefix all over, and you don't have to worry about conflicts with subroutine names in your program. – cjm Aug 29 '10 at 03:48
Does this work if `POSIX` was another script and not a Perl module ? Seems like it does not. – Jean Nov 11 '15 at 04:10

score 19 · Answer 3 · answered Aug 29 '10 at 04:37

19

You can exclude certain symbols from being normally exported with the '!name' directive (see perldoc Exporter), e.g.:

#!/usr/bin/perl -w
package Foo;

use strict;
use POSIX '!remove';

...

sub remove {
  ...
}
...

answered Aug 29 '10 at 04:37

Ether

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1

I didn't know about the '!name' directive! Neat! – Jim Davis Aug 30 '10 at 17:50

score -1 · Answer 4 · edited Sep 26 '18 at 14:02

-1

Subroutine XYZ redefined at line N [perl error]

You could wrap your routine in no warnings 'redefine' (which is lexically scoped):

no warnings 'redefine';

sub XYZ{

...
...

}

It worked for me!

edited Sep 26 '18 at 14:02

Jagat Dave

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answered Sep 26 '18 at 09:52

Sujitha Suresh

1

Welcome to StackOverflow: if you post code, XML or data samples, please highlight those lines in the text editor and click on the "code samples" button ( { } ) on the editor toolbar or using Ctrl+K on your keyboard to nicely format and syntax highlight it! – WhatsThePoint Sep 26 '18 at 10:06

How to handle subroutine redefined errors in Perl

4 Answers4