<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/127238>127238</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [libc] casting macro for user headers
        </td>
    </tr>

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

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

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

<pre>
    @enh-google saw our endian.h and mentioned `__BIONIC_CAST`.
https://android.googlesource.com/platform/bionic/+/main/libc/include/sys/cdefs.h#57
```c++
#if defined(__cplusplus)
#define __BIONIC_CAST(_k,_t,_v) (_k<_t>(_v))
#else
#define __BIONIC_CAST(_k,_t,_v) ((_t) (_v))
#endif
```
maybe interesting to add that to libc/include/__llvm-libc-common.h and use more in our user facing headers.
</pre>
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