Original link: https://ifmet.cn/posts/71bcb033/
Brief description: The respective meanings of WINUSERAPI and WINAPI frequently encountered in Window API.
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This article was originally published on ” Xie Zang’s Small Station “, and is reproduced here simultaneously.
background
In the research to realize the cross-platform AcrylicWindow acrylic (similar to transparent frosted) effect, when calling the Windows API, I found that the definition of its function is as follows, and I found that these two macros are a bit strange, so I was a little lost, so I checked the meaning of WINUSERAPI / WINAPI .
WINUSERAPI BOOL WINAPI SetWindowCompositionAttribute ( _In_ HWND hWnd , _Inout_ WINDOWCOMPOSITIONATTRIBDATA * pAttrData ) ;
WINUSERAPI
Indicates the import of a function
WINUSERAPI // 定义一# if ! defined ( _USER32_ ) # define WINUSERAPI DECLSPEC_IMPORT # else # define WINUSERAPI extern "C" # endif // 定义二# define DECLSPEC_IMPORT __declspec ( dllimport )
From the definition of the two-level meaning, WINUSERAPI roughly regarded as the keyword __declspec(dllimport);
__declspec(dllimport) means that you tell the compiler to explicitly import functions from the dll; especially when the class has a static member, the Link will basically fail without it. See this article
WINAPI
Commonly used macros WINAPI or CALLBACK to represent the __stdcall calling convention. Indicates that when parameters are pushed onto the stack, they are sequentially pushed onto the stack from right to left. Other calling conventions on your own Googel Keywords: function calling convention
1 #define CALLBACK __stdcall 2 #define WINAPI __stdcall
Serial address
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