Fixed bug #1056 (Frequent crashes in Touch events by simply touching the screen) Joseba García Echebarria 2010-12-15 01:55:22 PST I believe the crash is caused by a check not being performed on wether an SDL_Touch element is NULL before using it in the SDL_SendTouchMotion function in src/events/SDL_touch.c around line 400. Judging from the rest of the code, there's a missing if (!touch) { return 0; } before using "touch" as SDL_GetFinger(), SDL_GetFingerIndexId() use touch->num_fingers without checking. I can attach a patch if you like. It seems pretty straightforward, though. I have yet to discover why touch is being returned as NULL as this error is only triggered when an actual gesture has been performed, maybe something related to SDL_AddTouch()?

/* Print out all the scancodes we have, just to verify them */

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

#include "SDL.h"

int
main(int argc, char *argv[])
{
    SDL_ScanCode scancode;

    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
        exit(1);
    }
    for (scancode = 0; scancode < SDL_NUM_SCANCODES; ++scancode) {
        printf("Scancode #%d, \"%s\"\n", scancode,
               SDL_GetScancodeName(scancode));
    }
    SDL_Quit();
    return (0);
}