Windows 2000 and Unicode

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Windows 2000 is built from the ground up using Unicode. All of the core functions for creating windows, displaying text, performing string manipulations, and so forth require Unicode strings. If you call any Windows function and pass it an ANSI string, the system first converts the string to Unicode and then passes the Unicode string to the operating system. If you are expecting ANSI strings back from a function, the system converts the Unicode string to an ANSI string before returning to your application. All these conversions occur invisibly to you. Of course, there is time and memory overhead involved for the system to carry out all these string conversions.

For example, if you call CreateWindowEx and pass non-Unicode strings for the class name and window caption text, CreateWindowEx must allocate blocks of memory (in your process's default heap), convert the non-Unicode strings to Unicode strings and store the result in the allocated memory blocks, and make a function call to the Unicode version of CreateWindowEx.

For functions that fill buffers with strings, the system must convert from Unicode to non-Unicode equivalents before your application can process the string. Because the system must perform all these conversions, your application requires more memory and runs slower. You can make your application perform more efficiently by developing your application using Unicode from the start.