DBCS Support in Windows Versions 3.0 And 3.1

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.1 and 3.0

In a version of Windows that is enabled for double-byte character sets (DBCS), all functions that take strings as arguments will work with strings of double-byte characters. In addition, any version of Windows that supports DBCS will support the IsDBCSLeadByte function. This function determines whether or not a byte is the leading byte of a 2-byte character. The Windows functions that use a string length parameter (like lstrlen and TextOut) will use a count of bytes, not of characters. The functions IsDBCSLeadByte, AnsiPrev, and AnsiNext should be used to access characters within a string.

Note that DBCS-enabled Windows will typically have special methods to enter double-byte or composite characters. Composite character creation involves pressing several keys in a specified sequence to form new characters. The entry system is integrated into Windows by the original equipment manufacturer (hardware OEM). These characters are not typically directly entered into an edit control. Composite characters may be entered at the bottom of dialog box (as in OS/2). In many systems, these characters are composed at the bottom of the screen (in the composition window).

Copies of Windows version 3.0 developed for the United States and Europe do not support DBCS. Copies of Windows version 3.1 developed for the United States and Europe, and the KANJI adaptation of Windows version 3.0 and 3.1 do support DBCS. The KANJI adaptation of Windows is distributed through hardware OEMs. For more information on KANJI Windows, search this knowledge base on the following words:

   KANJI