Re: Strange C constructs

DoDI,


> My selfmade C preprocessor stumbled across a strange construct in one of
> the Windows headers. Now I would like to know whether this really makes
> sense:
>
> #define something /##/


It was probably surrounded by a #if that included:


#else
#define something
#endif


> I can imagine that the intended effect is the creation of an comment
> (// ...) in the source code, but IMO this is not achievable in
> accordance to any C/C++ standard.


Correct.


> Is this construct really a stupid Microsoft extension,


I imagine they have customers who think it is an intelligent extension.


> intended to
> prevent the compilation of Windows code with other compilers, or did I
> miss something in the newer C specs?


It does not prevent other compilers from processing this source. But
it does require that they support this construct.


> Another question may be easier to answer:
>
> typedef int (procname)(int arg);
>
> According to K&R only /pointers/ to procedure-types can be constructed.


Hang on. I thought you were a fan of standards?


> Does there exist newer specs which allow to typedef procedures
> themselves?


If you mean C99, then no. If you mean vendor extensions, I cannot
think of any.

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