const char * libmobi_msg(const MOBI_RET ret) {
    size_t index = ret;
    if (index < LIBMOBI_MSG_COUNT) {
        return libmobi_messages[index];
    }
    return "Unknown error";
}
const char * libmobi_msg(const MOBI_RET ret) {
    size_t index = ret;
    if (index < LIBMOBI_MSG_COUNT) {
        return libmobi_messages[index];
    }
    return "Unknown error";
}