view test/testsem.c @ 4106:12bb6311fd5d SDL-1.2

Hans de Goede fixed bug #495 When running boswars: http://www.boswars.org/ on a machine with intel integrathed graphics it crashes when it tries to play the initial theora splashscreen video: X Error of failed request: BadAlloc (insufficient resources for operation) Major opcode of failed request: 140 (XVideo) Minor opcode of failed request: 19 () Serial number of failed request: 25 Current serial number in output stream: 26 boswars: xcb_xlib.c:41: xcb_xlib_lock: Assertion `!c->xlib.lock' failed. Aborted I recognized this problem from a few years back, when I encountered it while working on the Xv blitter for xmame. The problem is that for some reason creation the Xvport and XvImage succeeds, and failure (lack of resources / hw capability?) is only indicated during the first XvPut[Shm]Image. I've written a patch for SDL using the work around for this I developed for xmame (and which is still used successfully in xmame after many years of usage). I'll admit it isn't very pretty, but after investigating several possibilities this was the best option, any other fixes would need changes to the SDL api and abi.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 29 Dec 2007 02:23:48 +0000
parents 290b5baf2fca
children 782fd950bd46 c121d94672cb 99acf3d856cb
line wrap: on
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/* 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;
}

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);
	SDL_Quit();
	return(0);
}