COMPARING MEMORY ISSUES

chuckd has asked for the wisdom of the Perl Monks concerning the following question:

can anyone tell me what the difference between:
%hash = ();
and
undef %hash;
is in terms of memory allocation?
Actually how would I undef a hash ref?
If my hash looks like this: $hashRef?

Comment on COMPARING MEMORY ISSUES

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Re: COMPARING MEMORY ISSUES by mikelieman (Friar) on Feb 05, 2009 at 21:33 UTC
One is empty. The other is undefined. undef $hashRef should do the trick, I'd think.	[reply]
Re^2: COMPARING MEMORY ISSUES by almut (Canon) on Feb 05, 2009 at 21:51 UTC
`undef $hashRef` should do the trick, I'd think. Yes, that would undef the reference itself — but that might not necessarily lead to the hash being undefined (which I think is what the OP is after...). `undef %$hashRef`, OTOH, would undefine the hash being referenced. But I suspect the real question here is "why is the associated memory not being freed?" :) If so, circular references (in data structures held in the hash) might be the reason... Object::Destroyer might help in this case. Also see Re^3: Large Memory for a list of related modules that might help with locating circular references.	[reply] [d/l] [select]