<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/74474>74474</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Bug]: Issues with std::format in libcxx
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            libc++
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          fl0at88
      </td>
    </tr>
</table>

<pre>
    ```
// helloworld.cpp

import <iostream>;
import <format>;

int main()
{
        std::cout << std::format("Hello, World of {}!" , "LLVM") << std::endl;
        return 0;
}
```

clang++ -Wall -Werror -std=c++20 -stdlib=libc++ -fmodules -fbuiltin-module-map -fuse-ld=lld -fexperimental-library helloworld.cpp -o App

Here are some of the errors I see:

```
ld.lld: error: undefined hidden symbol: std::__1::__itoa::__traits_base<unsigned __int128, void>::__width[abi:ue170005](unsigned __int128)
>>> referenced by helloworld.cpp
>>> /tmp/helloworld-781989.o:(std::__1::to_chars_result std::__1::__to_chars_itoa[abi:ue170005]<unsigned __int128>(char*, char*, unsigned __int128, std::__1::integral_constant<bool, false>))

ld.lld: error: undefined hidden symbol: std::__1::__itoa::__traits_base<unsigned __int128, void>::__convert[abi:ue170005](char*, unsigned __int128)
>>> referenced by helloworld.cpp
>>> /tmp/helloworld-781989.o:(std::__1::to_chars_result std::__1::__to_chars_itoa[abi:ue170005]<unsigned __int128>(char*, char*, unsigned __int128, std::__1::integral_constant<bool, false>))
clang++: error: linker command failed with exit code 1 (use -v to see invocation)

```
clang version 17.0.5
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsVU2P4zYM_TX0hXBgS_HaPviQjwl2ge21cwxki47VylIgyZmZf1_Ik8lkPWkvvfRQwFAIkXyi3mNE4b06GaIGii0U-0RMYbCu6XUmQlUlrZVvDXzLrl-2h2wD7ADsgANpbV-s03LVnc9X17yq8WxdQOA7ZX1wJEbgT8C3S29v3SjCve8aYQKOQhlgFbD66ilvIbUPEvgG-Kaz0wwEfIe3zStqzGXfY43Advgc60TbY8Qp98ByYAyjBxj7-fP334AxYPUXMDJS31VXOwqTM5h97pX7q7EgaV47LcwJ2BbYFtNnoTWmz-ScdZjOR-y7dyfL5g2tWuB7rdruI6cfrZw0eUz7dlI6KJO-76SjOGPaT55SHYG0lpj29Homp0YyQehUq9YJ97YQClOLm1_1-k6OUDhCb0eKJIWBcC7T4w_0RJGLu_jFVbVc6VjD5j0nGpOR1CtDEgclJRn0b2NrdXTdqD0e8w9DBSs-7OCECv7YCk_Ad5OZ21Pi8ahMyKOoO7xYJeeuec94UTIMUGxFq4BvJsrLLMsKKPbAqgf5Hw0VAeKHjnpyZDqS2C7ZWsYCO4TxDOzwGZaWVV5X9crGelj19X7BHrtBOH905CcdHjJwi5mpeHSXR1zwJ2BVzAO2icTcmQ-J-3qyMoFOTuhjZ40PwgTgu9ZaHaN7oaMGT5GyG2v_CcU7ay7kwt9o_s8s_C__v5D_7j37RX2tzJ_ksLPjKIzEXihNEl9UGJBeVcDOSsIc4x_SE6YXDDa-K6jMxXYiKGsWHbZ4YuZz8ULOK2swL1fZqkhkw2XNa5FQk5dZXlZFxXgyNLzndbWWousLIXnO11XXd1WWdywvWM1EohqWMZ6zrMjXeZmxlaC-qqp2LUtWtN94AeuMRqH0SuvLuLLulCjvJ2rK9bpcJ1q0pP08MBn7fKzjBCn2iWtiUtpOJw_rTCsf_CdMUEHPo3Y7nWZVN_gjIvt3rhYzDJXBiP_6mkxON0MIZz93WZy_JxWGqV11dgR2iAdcf9Kzs39QF4Ad5qI9sMNc918BAAD__wwBXcE">