p5pRT
commented
17 years ago From olly@survex.com
Created by olly@survex.com
"perldoc perlmod" says:
Like "CLONE"\, "CLONE_SKIP" is called once per package; however\, it is called just before cloning starts\, and in the context of the parent thread. If it returns a true value\, then no objects of that class will be cloned; or rather\, they will be copied as unblessed\, undef values.
But in my tests\, the copies are unblessed\, but aren't undef. Here's a simple example:
## Class.pm:
package Class;
use strict;
sub CLONE_SKIP { 1 }
sub new { bless {} }
1;
## cloneskip.pl:
#!/usr/bin/perl -W use strict; use Class; use threads;
my $obj = Class->new();
sub check_obj { my $where = shift; print "$where: ref(\$obj) = ".ref($obj)."\n"; print "$where: defined(\$obj) = ".defined($obj)."\n\n"; }
check_obj("main"); my $thread1 = threads->create(sub { check_obj("thread"); 1; } ); $thread1->join(); check_obj("main");
Output from "perl clone_skip.pl":
main: ref($obj) = Class main: defined($obj) = 1
thread: ref($obj) = SCALAR thread: defined($obj) = 1
main: ref($obj) = Class main: defined($obj) = 1
The documentation leads me to expect the third and fourth non-blank lines should be:
thread: ref($obj) = thread: defined($obj) =
as that is what I get if I change cloneskip.pl to do this:
my $thread1 = threads->create(sub { $obj = undef; check_obj("thread"); 1; } );
The documented behaviour seems sensible\, so I think the bug here is in the implementation rather than the documentation.
Cheers\, Olly
Migrated from rt.perl.org#47045 (status was 'resolved')
Searchable as RT47045$