1CORE(3pm)              Perl Programmers Reference Guide              CORE(3pm)
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NAME

6       CORE - Pseudo-namespace for Perl's core routines
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SYNOPSIS

9           BEGIN {
10               *CORE::GLOBAL::hex = sub { 1; };
11           }
12
13           print hex("0x50"),"\n";                     # prints 1
14           print CORE::hex("0x50"),"\n";               # prints 80
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DESCRIPTION

17       The "CORE" namespace gives access to the original built-in functions of
18       Perl. There is no "CORE" package, and therefore you do not need to use
19       or require an hypothetical "CORE" module prior to accessing routines in
20       this namespace.
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22       A list of the built-in functions in Perl can be found in perlfunc.
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OVERRIDING CORE FUNCTIONS

25       To override a Perl built-in routine with your own version, you need to
26       import it at compile-time. This can be conveniently achieved with the
27       "subs" pragma. This will affect only the package in which you've
28       imported the said subroutine:
29
30           use subs 'chdir';
31           sub chdir { ... }
32           chdir $somewhere;
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34       To override a built-in globally (that is, in all namespaces), you need
35       to import your function into the "CORE::GLOBAL" pseudo-namespace at
36       compile time:
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38           BEGIN {
39               *CORE::GLOBAL::hex = sub {
40                   # ... your code here
41               };
42           }
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44       The new routine will be called whenever a built-in function is called
45       without a qualifying package:
46
47           print hex("0x50"),"\n";                     # prints 1
48
49       In both cases, if you want access to the original, unaltered routine,
50       use the "CORE::" prefix:
51
52           print CORE::hex("0x50"),"\n";               # prints 80
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AUTHOR

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

58       perlsub, perlfunc.
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62perl v5.10.1                      2009-02-12                         CORE(3pm)