What does WINAPI mean and how is it related to the __stdcall calling convention?

Understanding the __stdcall Calling Convention in WINAPI Functions

In Windows programming, you may encounter the term "WINAPI" used in function signatures. This article aims to shed light on its significance and how it relates to the __stdcall calling convention.

What is WINAPI?

WINAPI stands for "Windows Application Programming Interface" and is a macro defined in the "windows.h" header file. It evaluates to __stdcall in the context of C code.

Calling Conventions

When functions call each other, they must adhere to specific conventions regarding how arguments are passed and stack cleanup. Different platforms and compilers have their own calling conventions.

__stdcall Calling Convention

__stdcall is a calling convention used in Microsoft Windows environments. It specifies that the caller allocates and initializes all arguments placed on the stack. However, the callee, or function being called, is responsible for cleaning up these arguments.

WINAPI and __stdcall

In the example code provided, "WINAPI WinMain" indicates that the WinMain function follows the __stdcall calling convention. This means that the arguments passed to WinMain (hInstance, hPrevInstance, lpCmdLine, and nCmdShow) will be cleaned up by WinMain itself.

Significance of WINAPI

Using the WINAPI macro ensures that your function conforms to the Windows calling convention. This is important for interoperability and avoiding stack corruption.

Conclusion

WINAPI is a macro that specifies the __stdcall calling convention in Windows programming. It helps ensure that caller and callee functions agree on how to manage the stack, preventing potential issues.

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