Re: cpp macros: quotes and spaces (# and ##)

[joost witteveen <joostje@cistron.nl>]

Je 1999/08/27(5)/19:08, joost witteveen montris sian geniecon skribante:
> I've got a define
> 
> #define WRAP_STAT __xstat
> 
> and from the macro WRAP_STAT, I want to define
> 
> #define NEXT_STAT next___xstat
>  and
> #define WRAP_STAT_QUOTE "__xstat"

[What doesn't work:]
> #define NEXT_STAT next_ ## WRAP_STAT
[..]
> #define QUOTE(a) #a
> #define WRAP_STAT_QUOTE QUOTE(WRAP_STAT)
[..]

OK, if everything else fails, read the docs. So, now I finally found
(in cpp.info, `Argument Prescan') how to do it. Still, I'd very much
like to hear if anyone knows how portable this is:

#define WRAP_STAT __xstat

#define NEXT_STAT(a,b,c) (CONCAT_LEVEL(WRAP_STAT))(a,b,c)
#define CONCAT_LEVEL(X)    CONCAT(X)
#define CONCAT(X)     next_ ## X
NEXT_STAT(1,2,3)

#define WRAP_STAT_QUOTE QUOTE_LEVEL(WRAP_STAT)
#define QUOTE_LEVEL(x) QUOTE_MACRO(x)
#define QUOTE_MACRO(y)  #y
WRAP_STAT_QUOTE

(at least for GNU cpp it works!)

> (Please also reply to me in person, as I am not subscribed to this
> list).

-- 
joostje