====== (This is the documentation for SDL3, which is under heavy development and the API is changing! [https://wiki.libsdl.org/SDL2/ SDL2] is the current stable version!) ====== = SDL_WaitThread = Wait for a thread to finish. == Syntax == void SDL_WaitThread(SDL_Thread * thread, int *status); == Function Parameters == {| |'''thread''' |the [[SDL_Thread]] pointer that was returned from the [[SDL_CreateThread]]() call that started this thread |- |'''status''' |pointer to an integer that will receive the value returned from the thread function by its 'return', or NULL to not receive such value back. |} == Remarks == Threads that haven't been detached will remain (as a "zombie") until this function cleans them up. Not doing so is a resource leak. Once a thread has been cleaned up through this function, the [[SDL_Thread]] that references it becomes invalid and should not be referenced again. As such, only one thread may call [[SDL_WaitThread]]() on another. The return code for the thread function is placed in the area pointed to by status, if status is not NULL. You may not wait on a thread that has been used in a call to [[SDL_DetachThread]](). Use either that function or this one, but not both, or behavior is undefined. It is safe to pass a NULL thread to this function; it is a no-op. Note that the thread pointer is freed by this function and is not valid afterward. == Version == This function is available since SDL 3.0.0. == Code Examples == #include "SDL.h" // Very simple thread - counts 0 to 9 delaying 50ms between increments static int TestThread(void *ptr) { int cnt; for (cnt = 0; cnt < 10; ++cnt) { SDL_Log("Thread counter: %d\n", cnt); SDL_Delay(50); } // Return the final value to the SDL_WaitThread function above return cnt; } int main(int argc, char *argv[]) { SDL_Thread *thread; int threadReturnValue; SDL_Log("Simple SDL_CreateThread test:"); // Simply create a thread thread = SDL_CreateThread(TestThread, "TestThread", (void *)NULL); if (NULL == thread) { SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL_CreateThread failed: %s\n", SDL_GetError()); } else { // Wait for the thread to complete. The thread functions return code will // be placed in the "threadReturnValue" variable when it completes. // SDL_WaitThread(thread, &threadReturnValue); SDL_Log("Thread returned value: %d\n", threadReturnValue); } return 0; } == Related Functions == :[[SDL_CreateThread]] :[[SDL_DetachThread]] ---- [[CategoryAPI]], [[CategoryThread]]