KSH_IGNORE_RDONLY
int no_ro_check = error_ok & KSH_IGNORE_RDONLY;
error_ok &= ~KSH_IGNORE_RDONLY;
error_ok |= KSH_IGNORE_RDONLY;
setstr(vp, val, KSH_UNWIND_ERROR | KSH_IGNORE_RDONLY);
setstr(vp, val, KSH_RETURN_ERROR | KSH_IGNORE_RDONLY);