Double-byte Character Sets

The double-byte character set (DBCS) is called an expanded 8-bit character set because its smallest unit is a byte. It can be thought of as the ANSI character set for some Asian versions of Microsoft® Windows NT® /Windows® 2000, Windows® 95, and Windows® 98 (particularly the Japanese versions). Win32 functions for the Japanese versions of Windows NT/Windows 2000, Windows 95, and Windows 98 accept DBCS strings for the ANSI versions of the functions. However, unlike the handling of Unicode, DBCS character handling requires detailed changes in the character-processing algorithms throughout an application's source code.

To help identify double-byte character sets, an application can use the IsDBCSLeadByte function to determine whether a given character is the first byte in a 2-byte character. In addition, an application can use the MultiByteToWideChar and WideCharToMultiByte functions to map DBCS strings to Unicode and map Unicode strings to DBCS strings.