pub type OSSL_i2d_of_void_ctx = Option<unsafe extern "C" fn(*const c_void, *mut *mut u8, *mut c_void) -> i32>;
enum OSSL_i2d_of_void_ctx { None, Some(unsafe extern "C" fn(*const c_void, *mut *mut u8, *mut c_void) -> i32), }
No value.
Some value of type T.
T