[Boost-users] Icompatibility between MS cl preprocessor and boost macro constructs

From: m.doppler_at_[hidden]
Date: 2003-09-19 10:34:42

Hi,

the header files boost/iterator_adaptors.hpp and 
boost/regex/v3/instances.hpp contain macro constructs that are icompatible 
with the Microsoft compiler cl when using them in a source file, 
preprocessing the source to a another source file and afterwards compiling 
the preprocessed source file.

For iterator_adaptors.hpp, cl version 13.00 is affected, for instances.hpp 
cl 13.00 and 13.10.

The problem can be reproduced by compiling the following simple source 
file (test.cpp) in the base boost directory (boost-1.30.2):

#include "boost/iterator_adaptors.hpp"
#include "boost/regex.hpp"

int main(void)
{
        return 0;
}

The commandline to preprocess the file is:
cl /TP /GX /EHsc /Zc:wchar_t /Zc:forScope /c /I. /P test.cpp

The commandline to compile the previously preprocessed file is:
cl /TP /GX /EHsc /Zc:wchar_t /Zc:forScope /c /I. test.i

Note that when directly compiling the same test program using the 
following commandline the problem disappears:
cl /TP /GX /EHsc /Zc:wchar_t /Zc:forScope /c /I. test.cpp

One might expect that the last command line should produce the same result 
as the first two, but unfortunately this is not the case.

I have attached a patch file that solves the icompatibility with the 
preprocessor by incorporating the following changes:

- In instances.hpp the patch adds single spaces between the 
BOOST_DEFAULT_ALLOCATOR and the end of some template declarations.

- In iterator_adaptors.hpp the conditional BOOST_WORKAROUND macros are 
refactored from inside the template declarations of 
indirect_iterator_generator and indirect_iterator_pair_generator to the 
front of them by duplicating the template struct definitions minus the 
BOOST_WORKAROUND code in the else branch of the conditional macro. 

In case you wonder why we need to preprocess the source file into a 
seperate file before compiling it:
This is required to use distcc (http://distcc.samba.org) with Microsofts 
cl.

Is there a chance this patch gets accepted for the next boost version?

Michael

--- michael doppler -----------------------------------
      developer
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      email: m.doppler_at_[hidden]
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