Function secp256k1_sys::secp256k1_ec_pubkey_serialize

pub unsafe extern "C" fn secp256k1_ec_pubkey_serialize(
    cx: *const Context, 
    output: *mut c_uchar, 
    out_len: *mut usize, 
    pk: *const PublicKey, 
    compressed: c_uint
) -> c_int