TITLE: identifying compiler support level with __cplusplus

(Newsgroups: comp.std.c++, 16 Mar 97)


UNKNOWN:

>> C++ compilers use to #define __cplusplus which can be used by source code
>> to check whether a C or C++ compiler is in use. Will that be part of the
>> C++ standard?
>> 
>> 	[Yes.  See 16.8[cpp.predefined]/1 in the draft working paper.
>> 		 -moderator (fjh).]


PALMER: "Sean L. Palmer" <seanpalmer@mindspring.com>

>
>What about draft/standard revision identification?  
>
>#if __cplusplus >= 19970211  //Feb '97 standard or later?
>#endif


HENDERSON: fjh@mundook.cs.mu.OZ.AU (Fergus Henderson)

See 16.8[cpp.predefined]/1!

If you read that, you will see that the Feb 97 draft requires
that __cplusplus be defined as `199711L'.  So you should use

	#if __cplusplus >= 199711  //Feb '97 standard or later?
	...
	#endif

PALMER:

>And a standard way for compiler vendors to identify themselves and their
>compiler version?

HENDERSON:

Compilers already have ways of doing that.

PALMER:

>#elif __compiler == __gnu

HENDERSON:

Why would that be any better than

	#elif __GNUC__