On 4/3/2011 2:01 PM, John Maddock wrote:
[...] My initial thought was to see if config could work with C compilers, but all investigation there has led me to believe that it would be too many unnecessary changes to config, would complicate config greatly, would need extensive testing against all compilers, and that since config is central to all of Boost such a potential massive change to it it is a bad idea. [...]
What about simply wrapping everything in config, except the varadic stuff, in an "#ifdef __cplusplus"?
That was the original thought. But it would mean testing each compiler/version to make sure that __cplusplus was actually being set when compiling a C++ program.
__cplusplus is absolutely required to be set for C++ compilation, I've never heard of a compiler that doesn't set it in C++ mode.
I believe you, but I did not know if you wanted this in config and/or trusted all the compilers config supports to implement this correctly. Of course I absolutely know they should...
It would be an unobtrusive change, and that define is required by every C++ standard I've seen (note: I've only seen working drafts, not the final copies, though I don't expect that part has changed).
It might be unobtrusive but there are very many config header files in which one would have to do that. Even doing it just for each compiler's header file would mean that each compiler would have to be tested which config supports. I do not think we even have every compiler which config supports being tested regularly, but I may be wrong.
True enough, but there weren't many changes required: try SVN Trunk now, Boost.Config should compile in C mode as well as C++ mode now. Tested locally with msvc, gcc (all the versions I could find!), intel and sun. I've also added a C-language test case, and manually inspected the compiler and platform config files for C++ specific code. Lets see how that works out...
Thank you very much. I will look at it, and report back my changes to allow variadic macro support checking without the need to have __cplusplus defined ( in other words for a C compiler ).