What is the correct way to define a UNICODE independent WinMain function?

Question

What is the correct way to define a UNICODE independent WinMain function for a Windows program that uses the CRT?

I am inclined to think that it should be something like

WINAPI
#ifdef UNICODE
  wWinMain
#else
  WinMain
#endif
 ( ... ) {
  ...
}

However, I am wondering if there is not already a predefined macro that expands to the correct symbol when compiling the source units (like those that are offered in the windows header files that expand to either WinApiFuncA or WinApiFuncW.

`_tWinMain` macro defined in *tchar.h* and expanded to `wWinMain` or `WinMain` — RbMm, Feb 22 '19 at 14:11
Possible duplicate of ["APIENTRY \_tWinMain" and "WINAPI WinMain" difference](https://stackoverflow.com/questions/4681443/apientry-twinmain-and-winapi-winmain-difference) — Axalo, Feb 22 '19 at 14:15
@Axalo: this is not about the differente of `WinMain` or `wWinMain` or `_tWinMain`, it's about how I correctly (or canonically) define `WinMain` in my source code. — René Nyffenegger, Feb 22 '19 at 14:19
@RbMm I don't think so. When I do a quick search for `#include.*tchar.h` in the CRT sources, I only find `.c` sources that include this file, but no `.h` sources. — René Nyffenegger, Feb 22 '19 at 14:20
@René You should use the Unicode variants as stated [here](https://learn.microsoft.com/en-us/windows/desktop/intl/unicode). — Axalo, Feb 22 '19 at 14:26
@RenéNyffenegger RbMms first comment is the answer. And yes you need to include ``. — Jabberwocky, Feb 22 '19 at 14:36
Not a duplicate, but this question may be of interest to you OP: https://stackoverflow.com/questions/234365/is-tchar-still-relevant — Govind Parmar, Feb 22 '19 at 17:30
People still supporting ANSI 15 years after it went out of style :D. — Cory Nelson, Feb 22 '19 at 17:50

Govind Parmar · Accepted Answer · 2019-02-22T17:44:36.733

In <tchar.h>, the macro _tWinMain expands to WinMain or wWinMain depending on project settings. This isn't enough, though; you need to declare the third argument (lpCmdLine) with the charset-agnostic LPTSTR too:

int APIENTRY _tWinMain(
    HINSTANCE hInstance, 
    HINSTANCE hPrevInstance, 
    LPTSTR lpCmdLine, 
    int nShowCmd
)

If Unicode is enabled on the project, this becomes LPWSTR, giving the signature:

int APIENTRY wWinMain(
    HINSTANCE hInstance, 
    HINSTANCE hPrevInstance, 
    LPWSTR lpCmdLine, 
    int nShowCmd
)

If Unicode is not enabled, you get the signature:

int APIENTRY WinMain(
    HINSTANCE hInstance, 
    HINSTANCE hPrevInstance, 
    LPSTR lpCmdLine, 
    int nShowCmd
)

What is the correct way to define a UNICODE independent WinMain function?

1 Answers1