On Sep 8, 2014, at 3:13 PM, lee wrote:
> Shawn H Corey <[email protected]> writes:
>
>> On Mon, 18 Aug 2014 16:17:53 +0800
>> Ken Peng <[email protected]> wrote:
>>
>>> sub myfunc {
>>> my @x=(1,2,3);
>>> return \@x;
>>> }
>>>
>>> # or,
>>>
>>> sub myfunc {
>>> my @x=(1,2,3);
>>> return [@x];
>>> }
>>
>> # or
>>
>> sub myfunc {
>> return [ 1, 2, 3 ];
>> }
>
> Is there a difference to
>
> sub myfunc {
> return ( 1, 2, 3 );
> }
The first example returns [ 1, 2, 3 ], which is a reference to a list with 3
elements. References are scalars.
The second example returns ( 1, 2, 3 ), which is a list with 3 elements.
So, yes, there is a difference.
> ? And my understanding was/is that in
>
> sub myfunc {
> my @x=(1,2,3);
> return \@x;
> }
>
> a reference would be returned to an array that ceases to exist when the
> function returning it has finished. At the point the function returns
> to, there isn't anything left the reference could refer to.
>
> Or is there?
Perl will not garbage-collect an element if there is a reference to it. So
while the array name @x no longer is in scope once the subroutine has returned,
the list that was the value of @x still exists in memory, and the reference
returned by the subroutine will be valid.
If the reference is not saved or copied, then the list will eventually get
garbage collected.
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