RE: [Boost-Users] min & max #undef'd by config.hpp?

From: richard_cox_at_[hidden]
Date: 2002-10-17 06:21:53

On 17 October 2002 09:14, Chris Russell [mailto:cdr_at_[hidden]] wrote:
> 
> I'm confused. Using MS Visual Studio 6.0 w/the Intel 6.0 
> compiler (or the
> native VC compiler for that matter) the min and max macros 
> are defined in
> the MS header WINDEF.H. It seems that config.hpp #undef's 
> these (although I
> haven't figured out where or why yet). My environment seems 
> to be perfectly
> happy using std::min/std::max. But what of all these 
> MS-defined macros that
> use the undecorated min/max? I really don't want to go 
> chasing these down in
> the MS + third-party headers if I can avoid it. Will someone 
> please explain
> to me what's going on with config.hpp?

There is nothing in windows.h that uses min & max. In fact if you define
NOMINMAX *before* you include windows.h they will not be defined.

> --- simple example ---
> 
> #include <windows.h>
> #include <boost/config.hpp>
> #if defined(min)
> #pragma message "min is defined"
> #else
> #pragma message "min not defined"
> #endif
> #if defined(max)
> #pragma message "max is defined"
> #else
> #pragma message "max not defined"
> #endif
> int main(int argc, char* argv[])
> {
> int a = 10, b = 20; int c = min(a,b); int d = max(a,b);
> return 0;
> }

You either need:

using std::min;
using std::max;

or fully qualify those names...

> 
> Deleting intermediate files and output files for project 'test - Win32
> Debug'.
> --------------------Configuration: test - Win32 
> Debug--------------------
> Compiling...
> StdAfx.cpp
> test.cpp
> . . . Boost configuring for Intel C++ compiler
> min not defined
> max not defined
> L:\boost\test\test.cpp(24): error: identifier "min" is undefined
>    int c = min(a,b);

... hence this error, there is no ::min.

> L:\boost\test\test.cpp(25): error: identifier "max" is undefined
>    int d = max(a,b);
>            ^

Richard Cox 
Senior Software Developer 
Dell Technology Online 
All opinions and statements mine and do not in any way (unless expressly
stated) imply anything at all on behalf of my employer