On Mon, Jul 14, 2008 at 08:32:52PM +0100, Paul LeoNerd Evans wrote:
> sub is_1ref
> {
> my ( undef, $name ) = @_;
> my $count = refcount($_[0]);
> ...
> }
>
> The $object in the first code creates a second reference, so you have to
> subtract 1, whereas the @_ array seems special and doesn't have that
> side-effect.
Until you take a reference to it, or various other things (I cant' remember the
canonical list, but push is in it, whereas shift doesn't seem to be (at least
a simple shift)):
$ perl -MDevel::Peek -e 'sub f {Dump $_[0]; warn [EMAIL PROTECTED]; Dump $_[0];
} f(\$v)'
SV = RV(0x817e18) at 0x800168
REFCNT = 1
FLAGS = (ROK)
RV = 0x800f18
SV = NULL(0x0) at 0x800f18
REFCNT = 2
FLAGS = ()
ARRAY(0x800f00) at -e line 1.
SV = RV(0x817e18) at 0x800168
REFCNT = 2
FLAGS = (ROK)
RV = 0x800f18
SV = NULL(0x0) at 0x800f18
REFCNT = 2
FLAGS = ()
It would be dangerous to rely on this reference counting behaviour remaining
the same.
Nicholas Clark
