Re: [xml] A long URL causes SEGV

[Daniel Veillard <veillard redhat com>]

On Mon, Feb 09, 2004 at 03:22:34PM +0100, Igor Zlatkovic wrote:
> That however doesn't happen. The C compiler, when doing a (...) && (...) 
> && (...), won't evaluate further parentheses after it encounters the 
> first one that evaluates to false. In our example, test for cur[1] is 
> false and an access to cur[2] doesn't happen.
>
> Question: Who can guarantee that all compilers really behave this way? 
> Is there anything in the C spec that forces the compiler to evaluate 
> these parentheses in exactly this manner?

  The C spec itself.
  There is an awful lot of code relying on the order of such compound
test, like for example
   if ((p != NULL) && (*p != 0))
you have the right to expect that if p is NULL the dereference will not occur.
It's the same for the test you pointed out, and in a lot of places in libxml2
code.

Daniel

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