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# CORE

Perl 5 version 12.2 documentation
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# CORE

- NAME
- SYNOPSIS
- DESCRIPTION
- OVERRIDING CORE FUNCTIONS
- AUTHOR
- SEE ALSO

# NAME

CORE - Pseudo-namespace for Perl's core routines

# SYNOPSIS

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

# DESCRIPTION

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.

# OVERRIDING CORE FUNCTIONS

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

# AUTHOR

This documentation provided by Tels <nospam-abuse@bloodgate.com> 2007.

# SEE ALSO

perlsub, perlfunc.

Page index

- NAME
- SYNOPSIS
- DESCRIPTION
- OVERRIDING CORE FUNCTIONS
- AUTHOR
- SEE ALSO