pub type dsetv_ft = Option<unsafe extern "C" fn(conjalpha: conj_t, n: dim_t, alpha: *mut f64, x: *mut f64, incx: inc_t)>;
enum dsetv_ft { None, Some(unsafe extern "C" fn(_: u32, _: i32, _: *mut f64, _: *mut f64, _: i32)), }
No value.
Some value of type T.
T