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static int shm_error;
static int (*X_handler)(Display *, XErrorEvent *) = NULL;
static bool have_mitshm(Display *dpy)
{
// Only use shared memory on local X servers
return X11_XShmQueryExtension(dpy) ? SDL_X11_HAVE_SHM : false;
}
static int shm_errhandler(Display *d, XErrorEvent *e)
{
if (e->error_code == BadAccess) {
shm_error = True;
return 0;
}
return X_handler(d, e);
}
{
if (have_mitshm(display)) {
XShmSegmentInfo shminfo;
shminfo.shmid = shmget(IPC_PRIVATE, (size_t)h * (*pitch), IPC_CREAT | 0777);
if (shminfo.shmid >= 0) {
shminfo.shmaddr = (char *)shmat(shminfo.shmid, 0, 0);
shminfo.readOnly = False;
if (shminfo.shmaddr != (char *)-1) {
shm_error = False;
X_handler = X11_XSetErrorHandler(shm_errhandler);
X11_XShmAttach(display, shminfo);
XSync(display, False);
X11_XSetErrorHandler(X_handler);
if (shm_error) {
shmdt(shminfo.shmaddr);
}
} else {
shm_error = True;
}
shmctl(shminfo.shmid, IPC_RMID, NULL);
} else {
shm_error = True;
}
if (!shm_error){
ximage = X11_XShmCreateImage(display, data->visual,
vinfo.depth, ZPixmap,
shminfo.shmaddr, shminfo,
w, h);
if (!ximage) {
X11_XShmDetach(display, shminfo);
X11_XSync(display, False);
shmdt(shminfo.shmaddr);
} else {
// Done!
ximage->byte_order = (SDL_BYTEORDER == SDL_BIG_ENDIAN) ? MSBFirst : LSBFirst;
*pixels = shminfo.shmaddr;
return true;
}
}
}
}
X11_XShmPutImage(display, data->xwindow, data->gc, data->ximage, x, y, x, y, w, h, False);
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