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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