I read the documentation about CreateWindowEx CreateWindowExA CreateWindowExW and they all are seem to be identical to each other.

if there is not difference why they all even exist?

CodePudding user response：

Firstly, CreateWindowEx is a macro, which expands to either CreateWindowExA or CreateWindowExW based on whether UNICODE has been defined. Many WinAPI functions work this way: they have a macro which switches between the appropriate functions based on UNICODE, then have the A and W versions.

Now, the difference with the A and W versions is fairly simple.

The "A" version handles text based on Windows code pages, while the "W" version handles Unicode text.

-- Source: https://docs.microsoft.com/en-us/windows/win32/intl/code-pages

From Microsoft documentation:

The winuser.h header defines CreateWindowEx as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.