[MSDN Library June 1998] __based; _based (100%)

MSDN Library Visual Studio 6.0 > Visual C++ Documentation > Using Visual C++ > Visual C++ Programmer's Guide > Language Quick Reference > C/C++ Keywords

[MSDN Library September 1992] __based (27.330779054917%)

Product Documentation > C/C++ 7.0 > C++ Language Reference > Appendix B Microsoft-Specific Modifiers > B.1 Memory-Model Modifiers