<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/97260>97260</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Clang Option] Can user prompt messages be output when using clang options that are compatible with gcc but not implemented?"
        </td>
    </tr>

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

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

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

<pre>
    On Apple M1 Pro, 
### example:
I have a file named uninit.cpp, the content is as follows.
```cpp
struct MyStruct {
    int uninitializedVariable; 
};

int main() {
    MyStruct myStruct;
        return myStruct.uninitializedVariable;
}
```


### Use gcc@14.1.0:
```shell
/opt/homebrew/opt/gcc@14/bin/g++-14 -Wuninitialized uninit.cpp 
uninit.cpp: In function 'int main()':
uninit.cpp:7:25: warning: 'myStruct.MyStruct::uninitializedVariable' is used uninitialized [-Wuninitialized]
    7 |         return myStruct.uninitializedVariable;
      | ^~~~~~~~~~~~~~~~~~~~~
uninit.cpp:6:14: note: 'myStruct' declared here
 6 |     MyStruct myStruct;
      | ^~~~~~~~
```

### Use clang@18.0.0: 
```shell
../bin/clang++ uninit.cpp -Wuninitialized 
# **I didn't get any information.**
```

The option **-Wuninitialized** is clang options that are compatible with gcc but not implemented.
But I don't know this information when i use clang on shell. Maybe more than just this one option has this problem.

However, since clang has no output (expect $? == 0), I might think that there are no uninitialized class member variables in my code, which could mislead me into thinking that my code meets my expectations. This could mislead normal users, **which is not in the style of friendly hint messages that clang usually provides.** I hope to change this by outputting some information to inform users that <span style="color:blue"> **some options**</span> in clang are merely for compatibility with gcc, but it is not implemented, so as not to mislead users.

If possible, please let me know as soon as possible that this is an valuable issue. I will make time to analyze the source code and address this problem.


</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJykVk2PozgQ_TXOpdQITGiSQw75mGhzaM1KO7t7NlAJnjY2sk0ymcP-9lXZhE5aPS2tNkIBbFfVq1fPZYRz8qQRV6zYsGI3E4NvjV29St0odD9boU-zyjTX1VcN675XCC8Z_G4N41tg6Y6la8bzeAH-EF2vkOXrOHOAVpwRBBylQtCiwwYGLbX0Sd335MG3CLXRHrUH6UA4OBqlzMUlo-_nNF60Pow4b4faw8v1j_jAyk2cAACQ2o8BpFDyJzZ_CStFRZA2N7TljuWjSfwno05IzfiC8eWjwylMNz7c2S4t-sHqaSr5VeS3wI853YN4T-WfDuFU12yeZvMkS9KJ08natajUzWxves_4vjUdVhYv08DNBeP7ijLcnxjfML55yubw9PcD4LvKjFTdlSpfw0HDcdC1l0YD4-Uja4yXE8IHMxrmBdlfhNVSn-iR8XIi7WUids3y9ccU8pLEMbgJ5A0yKzbvsmDF7q16JbByC7fffytXtCF7Vnz554PfB8k-s3ydzSlDbTy-y5SyaLBWwmIDLVoc4zxPIH8tto_AfCamBxnVSugTqWCRpEFI8GslJcmklGgW1HIvjfeqmSIC42vG1wdoZKMZLz2c0IPQV5D6aGwnSDlJXPQJ9m8tgulHldHa9wUOg6SHAHBc68C3woOw1E66XnhZKYSL9C3tIqgGTyUBSe2pQ-2xGRvMZvBwgMZExK_aXMC30t1jhkuLGiTp7xZTQ-AsgRdxrRA6Y5EAaPg-OB8dGD3l0QoXx3prKoVdcp_vb-aCZ7TUDJ3U9S0E2WgDZvD94IHxBf7okdodn7N8DyzfsXwHadh6WzhAJ09tiKxfIxWeJBYI0ebdrqmVcA467Cq0cB6FTylDd4XaNEguL62sW6jNoBropFMoGuiQOqyJYaQ-xUijEXSI3tFbhBq4cwl8o8wf_WiiVhGh1oVzJNQ0RpQuVkqHs8H5q0IwRzhaibpRV2hD40HnxAnHqkfGBjcIpa5E8lk26EapwQFa0yN4AzUdZhhLUV1Hbj3l4UxI7a3k3oyvEWSMw_Kt64WOoKgCnNdGGcvydaUGZJyz_MuYTPA4anPUfL5lfE8OaJXUI2yqUIcW1RWOxk7qlUr66yRgIok0LP3Ez5uSg3QMiDjhzURzgP4gtsMReuOcDE11C71C4RAUEqNR_MKBM0bT_bbypifaFQ6EhrNQA0kGpHMDJnCAi1QKOvGK4GUXuBZaqOtPjEU0gyVhk0iEbkA0jUX3yZ6YNau8WeZLMcNVVmbLRbYossWsXS0KsayX9XJR5NlyPj82R1E0z5ilxZwXzRJncsVTPk_LNEtLnhVlsqiPojlmZb3ERVY8N2yeYiekSpQ6d4mxp1lIYrUs-XM6U6JC5cKnEOdjA-T0VWRXtP6pGk6OzVMlnXdvHrz0Knw_bUNFv4aqs2IHW6FDESjJrr-TbYW3nR16y-BIhP-vn7F8zzifDVatWu97R-cp39OJL307VEltOsb3hHm8PfXWfEc6l_aBAsf4PrJwXvF_AwAA___QLj07">