The document is archived and information here might be outdated
Compiler Warning (level 1) C4237
Visual Studio 2005
Error Message'keyword' keyword is not yet supported, but reserved for future use
A keyword in the C++ specification is not implemented in the Visual C++ compiler, but the keyword is not available as a user-defined symbol.
The following sample generates C4237:
// C4237.cpp // compile with: /W1 /c int export; // C4237