Function hmac_memory_multi 

pub unsafe extern "C" fn hmac_memory_multi(
    hash: c_int,
    key: *const c_uchar,
    keylen: c_ulong,
    out: *mut c_uchar,
    outlen: *mut c_ulong,
    in_: *const c_uchar,
    inlen: c_ulong,
    ...
) -> c_int