Mercurial > sdl-ios-xcode
view test/testsem.c @ 5113:481dabb098ef
Improved timer implementation
The new timer model is formalized as using a separate thread to handle timer callbacks. This was the case on almost every platform before, but it's now a requirement, and simplifies the implementation and makes it perform consistently across platforms.
Goals:
* Minimize timer thread blocking
* Dispatch timers as accurately as possible
* SDL_AddTimer() and SDL_RemoveTimer() are completely threadsafe
* SDL_RemoveTimer() doesn't crash with a timer that's expired or removed
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Thu, 27 Jan 2011 14:45:06 -0800 |
parents | d547877e355e |
children |
line wrap: on
line source
/* Simple test of the SDL semaphore code */ #include <stdio.h> #include <stdlib.h> #include <signal.h> #include "SDL.h" #include "SDL_thread.h" #define NUM_THREADS 10 static SDL_sem *sem; int alive = 1; int SDLCALL ThreadFunc(void *data) { int threadnum = (int) (uintptr_t) data; while (alive) { SDL_SemWait(sem); fprintf(stderr, "Thread number %d has got the semaphore (value = %d)!\n", threadnum, SDL_SemValue(sem)); SDL_Delay(200); SDL_SemPost(sem); fprintf(stderr, "Thread number %d has released the semaphore (value = %d)!\n", threadnum, SDL_SemValue(sem)); SDL_Delay(1); /* For the scheduler */ } printf("Thread number %d exiting.\n", threadnum); return 0; } static void killed(int sig) { alive = 0; } static void TestWaitTimeout(void) { Uint32 start_ticks; Uint32 end_ticks; Uint32 duration; sem = SDL_CreateSemaphore(0); printf("Waiting 2 seconds on semaphore\n"); start_ticks = SDL_GetTicks(); SDL_SemWaitTimeout(sem, 2000); end_ticks = SDL_GetTicks(); duration = end_ticks - start_ticks; /* Accept a little offset in the effective wait */ if (duration > 1900 && duration < 2050) printf("Wait done.\n"); else fprintf(stderr, "Wait took %d milliseconds\n", duration); } int main(int argc, char **argv) { SDL_Thread *threads[NUM_THREADS]; uintptr_t i; int init_sem; if (argc < 2) { fprintf(stderr, "Usage: %s init_value\n", argv[0]); return (1); } /* Load the SDL library */ if (SDL_Init(0) < 0) { fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError()); return (1); } signal(SIGTERM, killed); signal(SIGINT, killed); init_sem = atoi(argv[1]); sem = SDL_CreateSemaphore(init_sem); printf("Running %d threads, semaphore value = %d\n", NUM_THREADS, init_sem); /* Create all the threads */ for (i = 0; i < NUM_THREADS; ++i) { threads[i] = SDL_CreateThread(ThreadFunc, (void *) i); } /* Wait 10 seconds */ SDL_Delay(10 * 1000); /* Wait for all threads to finish */ printf("Waiting for threads to finish\n"); alive = 0; for (i = 0; i < NUM_THREADS; ++i) { SDL_WaitThread(threads[i], NULL); } printf("Finished waiting for threads\n"); SDL_DestroySemaphore(sem); TestWaitTimeout(); SDL_Quit(); return (0); }