Langue: en

Version: 2007-12-18 (mandriva - 01/05/08)

Section: 3 (Bibliothèques de fonctions)


CORE - Pseudo-namespace for Perl's core routines


     BEGIN {
         *CORE::GLOBAL::hex = sub { 1; };
     print hex("0x50"),"\n";                     # prints 1
     print CORE::hex("0x50"),"\n";               # prints 80


The "CORE" namespace gives access to the original built-in functions of Perl. There is no "CORE" package, and therefore you do not need to use or require an hypothetical ``CORE'' module prior to accessing routines in this namespace.

A list of the built-in functions in Perl can be found in perlfunc.


To override a Perl built-in routine with your own version, you need to import it at compile-time. This can be conveniently achieved with the "subs" pragma. This will affect only the package in which you've imported the said subroutine:
     use subs 'chdir';
     sub chdir { ... }
     chdir $somewhere;

To override a built-in globally (that is, in all namespaces), you need to import your function into the "CORE::GLOBAL" pseudo-namespace at compile time:

     BEGIN {
         *CORE::GLOBAL::hex = sub {
             # ... your code here

The new routine will be called whenever a built-in function is called without a qualifying package:

     print hex("0x50"),"\n";                     # prints 1

In both cases, if you want access to the original, unaltered routine, use the "CORE::" prefix:

     print CORE::hex("0x50"),"\n";               # prints 80


This documentation provided by Tels <> 2007.


perlsub, perlfunc.