<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/118595>118595</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang++ cannot link g++ compiled library
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          WittonBell
      </td>
    </tr>
</table>

<pre>
    When using `Protobuf` in a project, because `Protobuf` relies on the `absl` library, under MinGW64, the `absl` library is compiled using the `gcc` compiler. If the project is compiled using the `clang` compiler, link failures will occur:
`
mingw64/include/absl/log/internal/log_message.h:135:(.text$_ZN4absl12lts_2024072212log_internal10LogMessagelsEy[_ZN4absl12lts_2024072212log_internal10LogMessagelsEy]+0x19): undefined reference to `_ZN4absl12lts_2024072212log_internal10LogMessagelsIyTnNSt9enable_ifIXntsr4absl16HasAbslStringifyIT_EE5valueEiE4typeELi0EEERS2_RKS5_'
`

I looked at the source code of the Absl library, version 2024072212:

`
LogMessage& operator<<(unsigned long long v) {  // NOLINT
 return operator<< <unsigned long long>(v);  // NOLINT
}

template <typename T,
          typename std::enable_if<!absl::HasAbslStringify<T>::value, int>::type>
LogMessage& LogMessage::operator<<(const T& v) {
  OstreamView view(*data_);
 view.stream() << log_internal::NullGuard<T>().Guard(v);
  return *this;
}

extern template LogMessage& LogMessage::operator<<(
    const unsigned long long& v);
`

The function signature generated by clang is different from the function signature generated by GCC. I don't know if clang has compilation options that can be fully compatible with GCC?
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJycVU1v4zYQ_TX0ZbCGRH1YOuhgO3ZqNJstNkZT9GJQ0khiQ5MGSdnxvy9IyUqQTVHsGoYEzcebxzfkkBnDW4lYkGRFkrsZ622ndPHMrVVyhULMSlVfi-cOJfSGyxZIGvyhlVVl35A0AC6BwUmrf7CyhK6hxIr1Bj-GaRQcDSgJtvNOVhrhHIKXmumrS-1ljRq-cnn_nMbO8HkocAOVOp64wHrkNAa2VeXiRqeew67xrpHefydWgsn2faqrLrh8gYZx0Ws0cOFCgKqqXpNoSYIlSQMSLI9cthdHdstlJfoaCd16unQrVOvNFrVko-FwRGNYi_OORMswShwUzeYWXy2h8eHvx9glh1RYc6ABjYMFpSF1iTecMHhQ7dcBRZjNlSSrX0u7I3QVvIY5oTmJll77hkusQWODGmWFYJXT5ufhd9e9fHyyOUpWCjzwZveXtEYPKOlvzCxLI56s5rLlzXW3P2w2yZmJHjd8E9vrCTcPPNhsNt-f6OH770_JgdDFpDgJljsQSr1gDcz6BhrV6wqhUjWCGjruKrzfWmfUhisJb_THLt5g3_gTmoI6oWZWaRKt3Z9mvfTHpAahZDs8zoTmQBYrAEK3hG7h8dvD7nFPgiVotL2WH1CAROsfYUi0ITQ7-y58AkUWdwNLi8eTYBYdipNIsiPCntC1qzf9Jo-xtVtgtJx64NcR-r3pHR_bQKL13pHxTt8NpxuXdjI6cPfxUax3Xz7uB_EqJY11ZNNJNM_6m7Ea2fFPjhc4c7wQmhG6rJllh0EPF-Uc8yHQ-3MY5Xy__4bCj70Q9z3T9W0tPn4-mCaRfemxQ4QubcfNYJ20xleHCpPkP7ncsSPDqj_p-CjDWPS2qfcdQtPLyrpt6nKY7TVCi9LBYw3lFfyYclOs5o0_pBYarY5-x_9f7v16PYcd1EoSurDwItUFeDNCduw2GZnHUCf3MmA7ZqFiEkpXQIirj2KWlwLhwm3nYEm0ndVFVOdRzmZYhIsoonmcJNmsK5qclVEcNmWaZiyOg0WUYFrVeZrSrInqesYLdyRDGsRBGtMom2f5Ig6TkuZplpd1kJE4wCPjYi7E-ThXup1xY3oswjBL8mQmWInC-NuL0mGMU-ouMl24hC9l3xoSB4Iba94gLLcCizF8RejKLVIqO8z8yXa7K8ZBMuu1KDprT8bPbXdSW267vpxX6ugGvDjfXl-mG3Hr6RpCtyPjc0H_DQAA__9qJ2A1">