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Bug 342

Summary: Crash on mode switch in SDL_SetCursor(NULL) with invisible software mouse cursor.
Product: SDL Reporter: bartoldeman
Component: videoAssignee: Ryan C. Gordon <icculus>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2    
Version: 1.2.11   
Hardware: x86   
OS: Linux   
Attachments: Small patch to test video driver cursor function are not NULL

Description bartoldeman 2006-10-08 16:09:26 UTC 
The following simple program

#include <SDL/SDL.h>

int main(void)
{
  SDL_Init(SDL_INIT_VIDEO);
  SDL_ShowCursor(SDL_DISABLE);
  SDL_SetVideoMode(640,480,8,0);
}

crashes:

#0  0x00000000 in ?? ()
#1  0x00d703bb in SDL_SetCursor () from /usr/lib/libSDL-1.2.so.0
#2  0x00d75d2c in SDL_SetVideoMode () from /usr/lib/libSDL-1.2.so.0
#3  0x080484f1 in main () at sdl.c:7

for all video output drivers with a software mouse cursor (e.g. aalib, fbdev).

The problem is in src/video/SDL_cursor.c, line 222.
video->ShowWMCursor(this, NULL);

I'm not sure what the best fix would be but checking
SDL_cursor->wm_cursor
seems logical.

There are various workarounds (without changing SDL): temporarily switching showing the cursor during a mode switch for instance.

Bart
Comment 1 Patrice Mandin 2006-11-16 14:11:12 UTC 
Created attachment 183 [details]
Small patch to test video driver cursor function are not NULL

There is still a fixme remaining as I don't know how I should fix it correctly
Comment 2 Patrice Mandin 2006-11-16 14:12:29 UTC 
Comment on attachment 183 [details]
Small patch to test video driver cursor function are not NULL

It happens when the video driver does not support mouse cursor (and related function pointers are NULL).
Comment 3 Patrice Mandin 2006-11-19 09:17:56 UTC 
Fixed in SDL-1.2 svn now.