pub unsafe extern "C" fn on_exit(
__func: Option<unsafe extern "C" fn(arg1: c_int, arg2: *mut c_void)>,
__arg: *mut c_void,
) -> c_intpub unsafe extern "C" fn on_exit(
__func: Option<unsafe extern "C" fn(arg1: c_int, arg2: *mut c_void)>,
__arg: *mut c_void,
) -> c_int