PRB: Using STL in Windows Program Can Cause Min/Max Conflicts

• Microsoft Visual C++, 32-bit Edition, version 4.0

SYMPTOMS

A windows-based program that uses the Standard Template Library (STL) will not compile, and it generates several invalid parameter and syntax errors.

CAUSE

The problem is caused by conflicting definitions of min and max. Min and max are defined as macros in Windef.h as follows:

   #ifndef NOMINMAX
   #ifndef max
   #define max(a,b)  (((a) > (b)) ? (a) : (b))
   #endif

   #ifndef min
   #define min(a,b)  (((a) < (b)) ? (a) : (b))
   #endif
   #endif  /* NOMINMAX */

Min and max are defined as templated functions in the Standard Template Library (STL). The following definitions of min and max can be found in the file Algobase.h:

   template <class T>
   inline const T& min(const T& a, const T& b) {
       return b < a ? b : a;
   }

   template <class T, class Compare>
   inline const T& min(const T& a, const T& b, Compare comp) {
       return comp(b, a) ? b : a;
   }

   template <class T>
   inline const T& max(const T& a, const T& b) {
       return  a < b ? b : a;
   }

   template <class T, class Compare>
   inline const T& max(const T& a, const T& b, Compare comp) {
       return comp(a, b) ? b : a;
   }

RESOLUTION

Simply define the NOMINMAX preprocessor symbol. This can be done in the Developer Studio project under Build, Settings, on the C/C++ tab, in the Preprocessor category. This will suppress the min and max definitions in Windef.h.

STATUS

This behavior is by design.

Keywords          : STLIss kb3rdparty
Version           : 4.0
Platform          : NT WINDOWS
Issue type        : kbprb
Solution Type     : Info_Provided