Function secp256k1_sys::secp256k1_ecdh

pub unsafe extern "C" fn secp256k1_ecdh(
    cx: *const Context,
    output: *mut c_uchar,
    pubkey: *const PublicKey,
    seckey: *const c_uchar,
    hashfp: EcdhHashFn,
    data: *mut c_void
) -> c_int