Why does C not accept the "const" qualifier as constant?

[Kevin P. Fleming]

On 10/10/2011 01:10 PM, Jochen Moeller wrote:
> Hello members,
>
> In a book I found some C++ code I changed to C but then got a compiler error which I
> don't understand. See the demo listings below, C versus C++.
>
> A const variable is not accepted for the definition of an array with constant size,
> and results in an error "Variable length array is not allowed at file scope" although
> the variable is defined as const.
>
> I tried some CFLAGS, used __const__ instead, and searched the archives without success.
>
> It seems that the "const" qualifier for the C-compiler is not really constant.
>
> Can this be explained and is it possible to avoid this error with some build options
> which I'm not aware of?

In C++, 'const int' is an actual compile-time constant. In C, it's just 
a non-writable variable. Not quite the same thing.

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Kevin P. Fleming
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