Re: [CIL users] static const

[Jan S. <jan...@al...>]

Apparently the problem is when this code gets heapified by CIL.

GCC 4.6 accepts this code at function scope but not at file scope.

Thanks for your answers.
- Jan

On 24/07/2012 11:00, Oliver Schwahn wrote:
> Hi,
> I also think that this is invalid C code. Initializers for static local
> variables have to be constant values. Variables with const modifier are
> not considered a constant value in this context (at least not by gcc,
> not sure what the standard says).
>
> So, the following code does also NOT work...
> const unsigned short a = 22;
> static unsigned short b = a - 1; /* a is not seen as constant value by
> gcc */
>
> The message "error: initializer element is not constant" is in fact a
> gcc error message stating exactly that.
>
> If you want to use a declared constant in such case, you can write
> something like...
> enum {a = 22};
> static unsigned short b = a - 1; /* now a is a constant int value and
> the expression is folded to 21 */
>
>
> The integer promotion you noticed is because of the used integer
> constant for arithmetics in "a - 1". Since "1" is a signed integer, "a"
> has to be promoted to a signed integer in order to compute the minus.
>
> Cheers
> Oliver
>
>
> 24.07.2012 07:48, Gabriel Kerneis:
>> On Mon, Jul 23, 2012 at 05:45:06PM +0200, Jan Smets wrote:
>>> Is this a valid coding error or a bug in cil ?
>>>     static const unsigned short b = a - 1;
>> This is a coding error (or at least gcc refuses to compile it).
>> Not sure about the integer promotion, though.
>>
>
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