ANSI Preprocessor Was: how widespread is this cpp bug?

[Arturo Perez Ext.]

>From article <9026 at smoke.BRL.MIL>, by gwyn at smoke.BRL.MIL (Doug Gwyn ):
> In article <6625 at csli.STANFORD.EDU> wagner at arisia.xerox.com (Juergen Wagner) writes:
>>      proc/**/VERSION
>>People relying on this bug should change their habits. There are better ways
>>to concatenate tokens.
> 
> No, for Reiser-based preprocessors there aren't any better ways.
> ANSI-style token pasting is fairly new, and many C implementations
> in current use do not support it.


I don't really know anything about the ANSI view of things.  All I know
is what I glean from this news group (And I must admit, I am impressed by
the high level of knowledge exhibited). 

Well, the upshot of all this is:  how do ANSI compilers allow the concatenating
of preprocessor macro parameters?  Under pcc you can do things like

#define MAC_RO1(string1, string2) "strings1string2"

If you feed MAC_RO1 like so

	MAC_RO1(dir, file)

you get

	"dirfile"

Can you accomplish anything similar with ANSI C?  I guess what I'm
asking for is a preprocessor tutorial in respect to ANSI-C.