view test/testlock.c @ 638:b0108e9dea53

Date: Sun, 11 May 2003 19:59:06 +0300 From: Pasi K?rkk?inen Subject: [PATCH] fix SDL OpenGL segfault with DRI/Mesa drivers and Glew Hello! The attached patch fixes a bug in SDL which causes SDL to crash in X11_GL_Shutdown() if you are using DRI/Mesa drivers AND glew (http://glew.sf.net). The bug is caused by a namespace collision affecting dlsym() to fetch wrong pointer for glXReleaseBuffersMESA() (uninitialized pointer from glew because the extension is NOT supported by the driver) and then SDL calling it in X11_GL_Shutdown(). SDL should check if the glXReleaseBuffersMESA() is really supported by the driver (from the extensions string) before calling it. Attached patch adds extension string parsing to check if glXReleaseBuffersMESA() is really supported (and this way prevents the segfault). Availability of the extensions should be _always_ checked from the extensions string rather than using dlsym()! Please add it to the next version of SDL. Thanks to gltron and author of glew to help fixing this.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 28 Jun 2003 17:27:33 +0000
parents 74212992fb08
children be9c9c8f6d53
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/* Test the thread and mutex locking functions 
   Also exercises the system's signal/thread interaction
*/

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

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

static SDL_mutex *mutex = NULL;
static Uint32 mainthread;
static SDL_Thread *threads[6];

void printid(void)
{
	printf("Process %u:  exiting\n", SDL_ThreadID());
}
	
void terminate(int sig)
{
	printf("Process %u:  raising SIGTERM\n", SDL_ThreadID());
	raise(SIGTERM);
}
void closemutex(int sig)
{
	Uint32 id = SDL_ThreadID();
	int i;
	printf("Process %u:  Cleaning up...\n", id == mainthread ? 0 : id);
	for ( i=0; i<6; ++i )
		SDL_KillThread(threads[i]);
	SDL_DestroyMutex(mutex);
	exit(sig);
}
int Run(void *data)
{
	if ( SDL_ThreadID() == mainthread )
		signal(SIGTERM, closemutex);
	while ( 1 ) {
		printf("Process %u ready to work\n", SDL_ThreadID());
		if ( SDL_mutexP(mutex) < 0 ) {
			fprintf(stderr, "Couldn't lock mutex: %s", SDL_GetError());
			exit(1);
		}
		printf("Process %u, working!\n", SDL_ThreadID());
		SDL_Delay(1*1000);
		printf("Process %u, done!\n", SDL_ThreadID());
		if ( SDL_mutexV(mutex) < 0 ) {
			fprintf(stderr, "Couldn't unlock mutex: %s", SDL_GetError());
			exit(1);
		}
		/* If this sleep isn't done, then threads may starve */
		SDL_Delay(10);
	}
	return(0);
}

int main(int argc, char *argv[])
{
	int i;
	int maxproc = 6;

	/* Load the SDL library */
	if ( SDL_Init(0) < 0 ) {
		fprintf(stderr, "%s\n", SDL_GetError());
		exit(1);
	}
	atexit(SDL_Quit);

	if ( (mutex=SDL_CreateMutex()) == NULL ) {
		fprintf(stderr, "Couldn't create mutex: %s\n", SDL_GetError());
		exit(1);
	}

	mainthread = SDL_ThreadID();
	printf("Main thread: %u\n", mainthread);
	atexit(printid);
	for ( i=0; i<maxproc; ++i ) {
		if ( (threads[i]=SDL_CreateThread(Run, NULL)) == NULL )
			fprintf(stderr, "Couldn't create thread!\n");
	}
	signal(SIGINT, terminate);
	Run(NULL);

	return(0);	/* Never reached */
}