[boost] win32.hpp and min/max macros

From: Eric Niebler (eric_at_[hidden])
Date: 2003-12-29 16:50:43

I just ran into an issue ralated to the use of Boost and MFC on Win32. 
The MFC file afxtempl.h relies on the max macro, which has been 
#undef'ed by config/platform/win32.hpp.  The following program, compiled 
with vc7.1, demonstrates the problem.

#include "boost/utility.hpp"
#include <afxtempl.h>

int main()
{
     CArray<int> array;
     array.SetSize(3);
     return 0;
}

f:\Program Files\Microsoft Visual Studio .NET 
2003\Vc7\atlmfc\include\afxtempl.h(398) : error C2668: 'std::max' : 
ambiguous call to overloaded function
         f:\boost\boost-1.30.2\boost\config\platform\win32.hpp(57): 
could be 'long std::max(long,long)'
         f:\boost\boost-1.30.2\boost\config\platform\win32.hpp(66): or 
      'long double std::max(long double,long double)'
         while trying to match the argument list '(INT_PTR, INT_PTR)'
         f:\Program Files\Microsoft Visual Studio .NET 
2003\Vc7\atlmfc\include\atlsimpstr.h(421) : while compiling 
class-template member function 'void CArray<TYPE>::SetSize(INT_PTR,INT_PTR)'
         with
         [
             TYPE=int
         ]
         f:\src\scratch_vc7\main.cpp(9) : see reference to class 
template instantiation 'CArray<TYPE>' being compiled
         with
         [
             TYPE=int
         ]

It seems extremely unwise to be undef'ing min and max.  Evil though they 
are, many Win32 platform headers (and users' headers!) depend on them, 
and there is simply no way to write a template or set of overloads that 
behave exactly as the macros do.

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com