view test/torturethread.c @ 1157:baf35853ad54

Date: Mon, 10 Oct 2005 13:09:32 +0300 From: Tommi Kyntola <tommi.kyntola@ray.fi> To: sdl@libsdl.org Subject: [SDL] [RFC] get_ticks broken on linux It uses gettimeofday to calculate the timedifference. Gettimeofday returns current time which is seldom monotonous. This breaks SDL timer subsystem. (time callbacks and all that get borked when the time difference ms is suddenly ~ 2^32) I posted a message about this earlier but got no response. Some thoughts on this matter would be appreciated. (Or even an explanation for the lack of interest.) A patch below would use the posix timers that have been around since posix 93 and do provide a good source of monotonous time on linux boxes (and on few others too). The following patch is also availabe at: http://www.hut.fi/u/tkyntola/SDL-1.2.9-clockfix.patch It's against 1.2.9, but I can easily rediffit against the cvs branch is needed. cheers, Tommi Kyntola tommi.kyntola@ray.fi
author Ryan C. Gordon <icculus@icculus.org>
date Tue, 11 Oct 2005 18:16:12 +0000
parents d93862a3d821
children 1dd8bf30a109
line wrap: on
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/* Simple test of the SDL threading code */

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>

#include "SDL.h"
#include "SDL_thread.h"

#define NUMTHREADS 10

static char volatile 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 SubThreadFunc(void *data) {
	while(! *(int volatile *)data) {
		; /*SDL_Delay(10);*/  /* do nothing */
	}
	return 0;
}

int ThreadFunc(void *data) {
	SDL_Thread *sub_threads[NUMTHREADS];
	int flags[NUMTHREADS];
	int i;
	int tid = (int ) data;

	fprintf(stderr, "Creating Thread %d\n", tid);

	for(i = 0; i < NUMTHREADS; i++) {
		flags[i] = 0;
		sub_threads[i] = SDL_CreateThread(SubThreadFunc, &flags[i]);
	}

	printf("Thread '%d' waiting for signal\n", tid);
	while(time_for_threads_to_die[tid] != 1) {
		; /* do nothing */
	}

	printf("Thread '%d' sending signals to subthreads\n", tid);
	for(i = 0; i <  NUMTHREADS; i++) {
		flags[i] = 1;
		SDL_WaitThread(sub_threads[i], NULL);
	}

	printf("Thread '%d' exiting!\n", tid);

	return 0;
}

int main(int argc, char *argv[])
{
	SDL_Thread *threads[NUMTHREADS];
	int i;

	/* Load the SDL library */
	if ( SDL_Init(0) < 0 ) {
		fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
		return(1);
	}

	signal(SIGSEGV, SIG_DFL);
	for(i = 0; i < NUMTHREADS; i++) {
		time_for_threads_to_die[i] = 0;
		threads[i] = SDL_CreateThread(ThreadFunc, (void *) i);
	
		if ( threads[i] == NULL ) {
			fprintf(stderr,
			"Couldn't create thread: %s\n", SDL_GetError());
			quit(1);
		}
	}

	for(i = 0; i < NUMTHREADS; i++) {
		time_for_threads_to_die[i] = 1;
	}

	for(i = NUMTHREADS-1; i >= 0; --i) {
		SDL_WaitThread(threads[i], NULL);
	}
	SDL_Quit();
	return(0);
}