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? - Thanks & regards Chris Russell --- 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; } 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); ^ L:\boost\test\test.cpp(25): error: identifier "max" is undefined int d = max(a,b); ^ compilation aborted for L:\boost\test\test.cpp (code 2) Error executing xicl6.exe. Creating browse info file... BSCMAKE: error BK1506 : cannot open file '.\Debug\test.sbr': No such file or directory Error executing bscmake.exe. test.exe - 3 error(s), 0 warning(s)