previously at http://anubis.dkuug.dk/jtc1/sc22/wg21/ , ISO/IEC JTC1/SC22/WG21 is the international standardization working group for the programming language C++.
these essays are intended for beginners, pointing out useful techniques. Some are for experienced programmers poking into previously unknown areas of MFC. Some are advanced techniques, highly specialized.
C and C++ compilers automatically define certain macros that can be used to check for compiler or operating system features. This is important when writing portable software.