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From: David Chisnall <theraven@FreeBSD.org>
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Subject: Re: svn commit: r240850 - head/lib/libstand
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On 23 Sep 2012, at 20:27, Garrett Cooper wrote:

>    +1. free(3) should silently ignore NULL parameters passed into it.

Indeed.  The C standard's description for free() states that:

> If ptr is a null pointer, no action occurs.

This means that a standards-compilant compiler is entirely at liberty to =
elide these checks (not sure if GCC or LLVM does, but both have =
optimisation passes that optimise based on assumptions about standard =
library functions, although they may not run when compiled in a =
freestanding environment).

The only reasons for a NULL check before free() should be:

- Sanity checking (i.e. this pointer is never meant to be NULL, assert =
that it isnt)
- Recursive cleanup (don't dereference this pointer to clean up its =
elements if it is NULL)

David=