Re: [boost] [preprocessor] computed include possible?

From: Roland Schwarz (roland.schwarz_at_[hidden])
Date: 2006-04-09 06:06:04

Tobias Schwinger wrote:
> Where is the problem?
[snip]
> 
>     #include PLATFORM_HEADER(foo.h)
> 
> Should work. I've no idea how portable it is, though. 
> 
This exactly is the problem. This works with MS compilers, but not with 
gcc. It complains with: #include' expects "FILENAME" or <FILENAME>"

However the following does work with gcc:

#define PLATFORM_PFX <boost/whatever/windows/

#define PLATFORM_HDR foo.hpp

#define PLATFORM_SFX >

#include PLATFORM_PFX PLATFORM_HDR PLATFORM_SFX

Unfortunately this wont work on MS compilers.

My question was if it would be possible to get something that is 
compileable on a couple of platforms. I am aware that macro expansion 
after precompiler prefix seems to be implementation dependent. I am not 
even sure if the standard has to say anything about this.

At least gcc seems not to conform to what is said in this (rather dated) 
document:
http://www.lns.cornell.edu/public/COMP/info/egcs/cpp/cpp_1.html#SEC6

Roland