ref: 666269029dbd79b2fdbe46131d853af9b2801cdf
dir: /external/SDL2/test/testsem.c/
/* Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org> This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely. */ /* Simple test of the SDL semaphore code */ #include <stdio.h> #include <stdlib.h> #include <signal.h> #include "SDL.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); SDL_Log("Thread number %d has got the semaphore (value = %d)!\n", threadnum, SDL_SemValue(sem)); SDL_Delay(200); SDL_SemPost(sem); SDL_Log("Thread number %d has released the semaphore (value = %d)!\n", threadnum, SDL_SemValue(sem)); SDL_Delay(1); /* For the scheduler */ } SDL_Log("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; int retval; sem = SDL_CreateSemaphore(0); SDL_Log("Waiting 2 seconds on semaphore\n"); start_ticks = SDL_GetTicks(); retval = 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) SDL_Log("Wait done.\n"); else SDL_Log("Wait took %d milliseconds\n", duration); /* Check to make sure the return value indicates timed out */ if (retval != SDL_MUTEX_TIMEDOUT) SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL_SemWaitTimeout returned: %d; expected: %d\n", retval, SDL_MUTEX_TIMEDOUT); } int main(int argc, char **argv) { SDL_Thread *threads[NUM_THREADS]; uintptr_t i; int init_sem; /* Enable standard application logging */ SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO); if (argc < 2) { SDL_Log("Usage: %s init_value\n", argv[0]); return (1); } /* Load the SDL library */ if (SDL_Init(0) < 0) { SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "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); SDL_Log("Running %d threads, semaphore value = %d\n", NUM_THREADS, init_sem); /* Create all the threads */ for (i = 0; i < NUM_THREADS; ++i) { char name[64]; SDL_snprintf(name, sizeof (name), "Thread%u", (unsigned int) i); threads[i] = SDL_CreateThread(ThreadFunc, name, (void *) i); } /* Wait 10 seconds */ SDL_Delay(10 * 1000); /* Wait for all threads to finish */ SDL_Log("Waiting for threads to finish\n"); alive = 0; for (i = 0; i < NUM_THREADS; ++i) { SDL_WaitThread(threads[i], NULL); } SDL_Log("Finished waiting for threads\n"); SDL_DestroySemaphore(sem); TestWaitTimeout(); SDL_Quit(); return (0); }