mirror of
https://github.com/Relintai/sdl2_frt.git
synced 2024-12-16 11:06:49 +01:00
fa8c83c1c1
As Tiffany pointed out in Bugzilla, volatile is not useful for thread safety: https://software.intel.com/en-us/blogs/2007/11/30/volatile-almost-useless-for-multi-threaded-programming/ Some of these volatiles didn't need to be, some were otherwise protected by spinlocks or mutexes, and some got moved over to SDL_atomic_t data, etc. Fixes Bugzilla #3220.
114 lines
2.8 KiB
C
114 lines
2.8 KiB
C
/*
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Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely.
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*/
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/* Simple test of the SDL threading code */
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <string.h>
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#include "SDL.h"
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#define NUMTHREADS 10
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static SDL_atomic_t time_for_threads_to_die[NUMTHREADS];
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/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
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static void
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quit(int rc)
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{
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SDL_Quit();
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exit(rc);
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}
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int SDLCALL
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SubThreadFunc(void *data)
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{
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while (!*(int volatile *) data) {
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; /* SDL_Delay(10); *//* do nothing */
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}
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return 0;
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}
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int SDLCALL
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ThreadFunc(void *data)
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{
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SDL_Thread *sub_threads[NUMTHREADS];
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int flags[NUMTHREADS];
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int i;
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int tid = (int) (uintptr_t) data;
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SDL_Log("Creating Thread %d\n", tid);
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for (i = 0; i < NUMTHREADS; i++) {
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char name[64];
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SDL_snprintf(name, sizeof (name), "Child%d_%d", tid, i);
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flags[i] = 0;
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sub_threads[i] = SDL_CreateThread(SubThreadFunc, name, &flags[i]);
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}
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SDL_Log("Thread '%d' waiting for signal\n", tid);
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while (SDL_AtomicGet(&time_for_threads_to_die[tid]) != 1) {
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; /* do nothing */
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}
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SDL_Log("Thread '%d' sending signals to subthreads\n", tid);
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for (i = 0; i < NUMTHREADS; i++) {
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flags[i] = 1;
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SDL_WaitThread(sub_threads[i], NULL);
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}
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SDL_Log("Thread '%d' exiting!\n", tid);
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return 0;
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}
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int
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main(int argc, char *argv[])
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{
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SDL_Thread *threads[NUMTHREADS];
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int i;
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/* Enable standard application logging */
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SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
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/* Load the SDL library */
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if (SDL_Init(0) < 0) {
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SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
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return (1);
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}
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signal(SIGSEGV, SIG_DFL);
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for (i = 0; i < NUMTHREADS; i++) {
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char name[64];
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SDL_snprintf(name, sizeof (name), "Parent%d", i);
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SDL_AtomicSet(&time_for_threads_to_die[i], 0);
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threads[i] = SDL_CreateThread(ThreadFunc, name, (void*) (uintptr_t) i);
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if (threads[i] == NULL) {
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SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create thread: %s\n", SDL_GetError());
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quit(1);
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}
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}
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for (i = 0; i < NUMTHREADS; i++) {
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SDL_AtomicSet(&time_for_threads_to_die[i], 1);
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}
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for (i = 0; i < NUMTHREADS; i++) {
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SDL_WaitThread(threads[i], NULL);
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}
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SDL_Quit();
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return (0);
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}
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