[asterisk-dev] [Code Review]: automagically set a pointer to null after it is freed with ast_free

[Simon Perreault]

David Vossel wrote, on 09/16/2011 10:47 AM:
> I don't think we can change the behavior of ast_free(), but this functionality seems useful.  I write the following lines all the time.
> 
> ast_free(blah);
> blah = NULL;

Well, you should stop doing that, for the reasons previously stated.

Here's a "prisoner's dilemma-style" matrix to illustrate:

                    | Set to null     | Do not set to null
--------------------+-----------------+------------------------------------
Double free         | Undetectable    | Detectable with Valgrind or similar
Use of freed memory | Immediate crash | Detectable with Valgrind or similar

As you can see, the "do not set to null" option is better overall.

Simon
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