gdb ./testalpha

Program received signal SIGSEGV, Segmentation fault.
0x001e21da in X11_DestroyWindowFramebuffer (_this=0x804ed80, window=0x808f370) at src/video/x11/SDL_x11framebuffer.c:193
193         Display *display = data->videodata->display;
Missing separate debuginfos, use: debuginfo-install expat-2.0.1-11.fc15.i686 libX11-1.4.3-1.fc15.i686 libXScrnSaver-1.2.1-2.fc15.i686 libXau-1.0.6-2.fc15.i686 libXcursor-1.1.11-3.fc15.i686 libXdamage-1.1.3-2.fc15.i686 libXext-1.2.0-2.fc15.i686 libXfixes-5.0-1.fc15.i686 libXi-1.4.3-1.fc15.i686 libXinerama-1.1.1-2.fc15.i686 libXrandr-1.3.1-2.fc15.i686 libXrender-0.9.6-2.fc15.i686 libXxf86vm-1.1.1-2.fc15.i686 libdrm-2.4.26-1.fc15.i686 libgcc-4.6.0-9.fc15.i686 libselinux-2.0.99-4.fc15.i686 libstdc++-4.6.0-9.fc15.i686 libxcb-1.7-2.fc15.i686 mesa-dri-drivers-7.11-0.16.20110709.0.fc15.i686 mesa-dri-llvmcore-7.11-0.16.20110709.0.fc15.i686 mesa-libGL-7.11-0.16.20110709.0.fc15.i686

(gdb) bt
#0  0x001e21da in X11_DestroyWindowFramebuffer (_this=0x804ed80, window=0x808f370) at src/video/x11/SDL_x11framebuffer.c:193
#1  0x001d62ec in SDL_DestroyWindow (window=0x808f370) at src/video/SDL_video.c:1949
#2  0x001d44fb in SDL_CreateWindow (title=0x1f4014 "OpenGL test", x=-32, y=-32, w=32, h=32, flags=10) at src/video/SDL_video.c:1187
#3  0x001d21f1 in ShouldUseTextureFramebuffer () at src/video/SDL_video.c:169
#4  0x001d2d22 in SDL_VideoInit (driver_name=0x0) at src/video/SDL_video.c:509
#5  0x0011a84d in SDL_InitSubSystem (flags=32) at src/SDL.c:55
#6  0x0011a9ad in SDL_Init (flags=32) at src/SDL.c:150
#7  0x0804979a in main (argc=1, argv=0xbffff384) at testalpha.c:358

(gdb) print *window
$1 = {magic = 0x804ee4c, id = 1, title = 0x0, x = -32, y = -32, w = 32, h = 32, flags = 10, windowed = {x = 0, y = 0, w = 0, h = 0}, fullscreen_mode = {
    format = 0, w = 0, h = 0, refresh_rate = 0, driverdata = 0x0}, brightness = 1, gamma = 0x0, saved_gamma = 0x0, surface = 0x0, surface_valid = SDL_FALSE,
  shaper = 0x0, data = 0x0, driverdata = 0x0, prev = 0x0, next = 0x0}