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From: =?ISO-8859-1?Q?Hans-Bernhard_Br=F6ker?= <HBBroeker@t-online.de>
Newsgroups: comp.std.c
Subject: Re: VLAs use less stack
Date: Tue, 04 Sep 2012 00:03:48 +0200
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On 03.09.2012 00:45, John Nagle wrote:

>     If the program isn't recursive, and you do code coverage tests,
> so that the worst case stack depth has been exercised,

It's relatively easy to prove that this is impossible to achieve in the 
general case.  Even without VLAs you run into problems as soon as you 
have function pointer variables involved, because trying to predict 
which functions those can possibly point to, short of actually running 
the program with all possible inputs, is generally equivalent to the 
Halting Problem.  VLAs make that even more impossible, because even if 
you can build a known-complete call tree that still doesn't give you the 
actual stack size.