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Re: Using `const int' values to size stack arrays

From: Robert Dewar <dewar at gnat dot com>
To: Nathan Sidwell <nathan at codesourcery dot com>
Cc: Daniel Towner <daniel dot towner at picochip dot com>, gcc at gcc dot gnu dot org
Date: Wed, 17 Nov 2004 06:12:33 -0500
Subject: Re: Using `const int' values to size stack arrays
References: <419B27C3.3010009@picochip.com> <419B2C06.1080306@codesourcery.com>

Nathan Sidwell wrote:

I presume we're talking C here, and gnu C at that.
MAX_VAL is not an integral constant expression, so int ary[MAX_VAL]
must be a VLA, if it is valid.

C89 disallows both uses,
C99 disallows VLAs at file scope, but allows them at function scope.
GNU C is similar to C99.


Of course, since GNU C allows dynamic arrays, it does allow this
construct, and given that it is allowed, it is perfectly reasonable
to ask that the compiler do this efficiently and not actually treat
it as dynamic at the implementation level (even if it is dynamic at
the semantic level).

Follow-Ups:
- Re: Using `const int' values to size stack arrays
  - From: Daniel Towner

References:
- Using `const int' values to size stack arrays
  - From: Daniel Towner
- Re: Using `const int' values to size stack arrays
  - From: Nathan Sidwell

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