SwitchBufPtrs(screen) register TScreen *screen;
SwitchBufPtrs(register TScreen *screen)
SwitchBufPtrs(screen)    register TScreen *screen;{    size_t len = ScrnPointers(screen, screen->max_row + 1);    memcpy ( (char *)screen->save_ptr, (char *)screen->visbuf,   len);    memcpy ( (char *)screen->visbuf,   (char *)screen->altbuf,   len);    memcpy ( (char *)screen->altbuf,   (char *)screen->save_ptr, len);}