Re: [boost] win32.hpp and min/max macros

From: John Maddock (john_at_[hidden])
Date: 2003-12-30 06:25:46

> 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;
> }
> 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.

I agree - but there is plenty of boost code that relies on std::min and
std::max *not* being macros - were we not to do this then a fair portion of
Boost would just stop working :-(

There is BTW a trivial fix for your problem: include the windows headers
*before* any Boost ones.

However, there is also a bug in our workaround - we haven't include
<algorithm> to get the template min/max functions as well as the additional
overloads that we add in the workaround, and it's this that is the cause of
the error in this case, I'm committing a revised win32.hpp which will now
compile the sample you posted (or will be as soon as the config regression
tests complete).

John.