pub type i2d_of_void = Option<unsafe extern "C" fn(arg1: *const c_void, arg2: *mut *mut c_uchar) -> c_int>;
enum i2d_of_void { None, Some(unsafe extern "C" fn(_: *const c_void, _: *mut *mut u8) -> i32), }
No value.
Some value of type T.
T