By using C/C++ with message crackers to present the sample code in this book, I get to introduce these little-known but useful macros to many people who might not know about them.
Message crackers are in the WindowsX.h file supplied with Microsoft Visual Studio. You usually include this file immediately after the Windows.h file. The WindowsX.h file is nothing more than a bunch of
#define directives that create a set of macros for you to use. The macros in WindowsX.h are actually divided into three groups: message crackers, child control macros, and application programming interface (API) macros. These macros help you in the following ways:
They reduce the amount of casting you need ...