<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/78657>78657</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            The return value of `column()` obtained from `std::source_location::current()` should be documented
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          frederick-vs-ja
      </td>
    </tr>
</table>

<pre>
    Per standard requirements ([N4868 [source.srcloc.cons]/1.1](https://timsong-cpp.github.io/cppwp/n4868/support.srcloc.cons#1.1), [N4868 [support.srcloc.obs]/2](https://timsong-cpp.github.io/cppwp/n4868/support.srcloc.obs#2)), the return value of `column()` obtained from `std::source_location::current()` is implementation-defined and thus should be documented.

Currently, `__builtin_COLUMN` and `__builtin_source_location` are mentioned in [this page](https://clang.llvm.org/docs/LanguageExtensions.html#source-location-builtins), but their values are not well-documented.

Documentations of implementations would be helpful when one wants use `column()`, as there's implementation divergence (can be found in [this test file in MSVC STL](https://github.com/microsoft/STL/blob/0cb9eb45b5d13015a28670a47b6c9760038d3e66/tests/std/tests/P1208R6_source_location/test.cpp)).
</pre>
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