This works for me under 5.016003 even without the correct prototype:

use strict;
use warnings;

warn "Version $]";
warn "Prototype", prototype "CORE::sleep";


my $sleepcounter;


BEGIN {
    *CORE::GLOBAL::sleep =  sub {
        warn  "start wrapper";
        $sleepcounter += $_[0];
        CORE::sleep(@_);
        warn  "stop wrapper";
    };
}


sleep 3;

warn "total sleep( $sleepcounter )"

[download]
C:/Perl_64/bin\perl.exe  d:/Users/lanx/pm/core_sleep.pl 
Version 5.016003 at d:/Users/lanx/pm/core_sleep.pl line 4.
Prototype;$ at d:/Users/lanx/pm/core_sleep.pl line 5.
start wrapper at d:/Users/lanx/pm/core_sleep.pl line 13.
stop wrapper at d:/Users/lanx/pm/core_sleep.pl line 16.
total sleep( 3 ) at d:/Users/lanx/pm/core_sleep.pl line 26.

[download]

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

In reply to Re^2: Copy a builtin sub to a different name and then override by LanX
in thread Copy a builtin sub to a different name and then override by bliako

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