The extended character set that Windows and Windows programs use for most purposes is called the ”ANSI character set.“ When your program receives a WM_CHAR message, the wParam parameter is the ANSI character code. The ANSI character set is shown in Figure 3-8. As you can see, the codes from 20H through 7EH represent the same characters that appear in the OEM character set and the ASCII character set. The characters displayed as solid blocks are undefined characters. They may appear differently on other output devices (such as a printer).