SDL/test/torturethread.c
Ryan C. Gordon fa8c83c1c1 Remove almost all instances of "volatile" keyword.
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.
2016-01-03 06:50:50 -05:00

114 lines
2.8 KiB
C

/*
Copyright (C) 1997-2016 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 threading code */
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include "SDL.h"
#define NUMTHREADS 10
static SDL_atomic_t time_for_threads_to_die[NUMTHREADS];
/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void
quit(int rc)
{
SDL_Quit();
exit(rc);
}
int SDLCALL
SubThreadFunc(void *data)
{
while (!*(int volatile *) data) {
; /* SDL_Delay(10); *//* do nothing */
}
return 0;
}
int SDLCALL
ThreadFunc(void *data)
{
SDL_Thread *sub_threads[NUMTHREADS];
int flags[NUMTHREADS];
int i;
int tid = (int) (uintptr_t) data;
SDL_Log("Creating Thread %d\n", tid);
for (i = 0; i < NUMTHREADS; i++) {
char name[64];
SDL_snprintf(name, sizeof (name), "Child%d_%d", tid, i);
flags[i] = 0;
sub_threads[i] = SDL_CreateThread(SubThreadFunc, name, &flags[i]);
}
SDL_Log("Thread '%d' waiting for signal\n", tid);
while (SDL_AtomicGet(&time_for_threads_to_die[tid]) != 1) {
; /* do nothing */
}
SDL_Log("Thread '%d' sending signals to subthreads\n", tid);
for (i = 0; i < NUMTHREADS; i++) {
flags[i] = 1;
SDL_WaitThread(sub_threads[i], NULL);
}
SDL_Log("Thread '%d' exiting!\n", tid);
return 0;
}
int
main(int argc, char *argv[])
{
SDL_Thread *threads[NUMTHREADS];
int i;
/* Enable standard application logging */
SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
/* 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(SIGSEGV, SIG_DFL);
for (i = 0; i < NUMTHREADS; i++) {
char name[64];
SDL_snprintf(name, sizeof (name), "Parent%d", i);
SDL_AtomicSet(&time_for_threads_to_die[i], 0);
threads[i] = SDL_CreateThread(ThreadFunc, name, (void*) (uintptr_t) i);
if (threads[i] == NULL) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create thread: %s\n", SDL_GetError());
quit(1);
}
}
for (i = 0; i < NUMTHREADS; i++) {
SDL_AtomicSet(&time_for_threads_to_die[i], 1);
}
for (i = 0; i < NUMTHREADS; i++) {
SDL_WaitThread(threads[i], NULL);
}
SDL_Quit();
return (0);
}