# SDL_RegisterApp Register a win32 window class for SDL's use. ## Header File Defined in [<SDL3/SDL_main.h>](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_main.h) ## Syntax ```c bool SDL_RegisterApp(const char *name, Uint32 style, void *hInst); ``` ## Function Parameters | | | | | ---------------- | --------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- | | const char * | **name** | the window class name, in UTF-8 encoding. If NULL, SDL currently uses "[SDL_app](SDL_app)" but this isn't guaranteed. | | [Uint32](Uint32) | **style** | the value to use in WNDCLASSEX::style. If `name` is NULL, SDL currently uses `(CS_BYTEALIGNCLIENT | CS_OWNDC)` regardless of what is specified here. | | void * | **hInst** | the HINSTANCE to use in WNDCLASSEX::hInstance. If zero, SDL will use `GetModuleHandle(NULL)` instead. | ## Return Value (bool) Returns true on success or false on failure; call [SDL_GetError](SDL_GetError)() for more information. ## Remarks This can be called to set the application window class at startup. It is safe to call this multiple times, as long as every call is eventually paired with a call to [SDL_UnregisterApp](SDL_UnregisterApp), but a second registration attempt while a previous registration is still active will be ignored, other than to increment a counter. Most applications do not need to, and should not, call this directly; SDL will call it when initializing the video subsystem. ## Version This function is available since SDL 3.2.0. ---- [CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction), [CategoryMain](CategoryMain)