wWinMain

wWinMain is the Unicode entry point for Windows GUI applications. It is the wide-character counterpart to WinMain and is used when building a Windows desktop application that relies on Unicode for command-line arguments and text. In many development environments, including Visual Studio templates, wWinMain serves as the program’s entry point.

Signature and parameters: int APIENTRY wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine, int nCmdShow). The hInstance parameter is a handle to the current instance; hPrevInstance is typically NULL on modern Windows systems. pCmdLine is the command-line string in Unicode (the arguments, excluding the program name). nCmdShow indicates how the main window should be shown initially.

Usage and behavior: wWinMain returns an int exit code to Windows when the application terminates. When a GUI app starts, Windows typically transfers control to wWinMain via the CRT startup code (such as wWinMainCRTStartup), which initializes the C runtime before invoking wWinMain. Inside this function, a program usually creates its main window, runs the message loop, and processes events until the application exits. If needed, command-line arguments can be parsed with CommandLineToArgvW.

Relation to WinMain and main: wWinMain is used for Unicode GUI applications, while WinMain is the ANSI counterpart. Console applications may provide a main function instead, depending on the subsystem setting. The choice between wWinMain and WinMain is determined by project configuration and whether Unicode support is required.