Function in3_sys::ecdsa_sign_digest

pub unsafe extern "C" fn ecdsa_sign_digest(
    curve: *const ecdsa_curve, 
    priv_key: *const u8, 
    digest: *const u8, 
    sig: *mut u8, 
    pby: *mut u8, 
    is_canonical: Option<unsafe extern "C" fn(by: u8, sig: *mut u8) -> c_int>
) -> c_int