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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - __has_c_attribute in C++ mode"
href="https://bugs.llvm.org/show_bug.cgi?id=44137">44137</a>
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<th>Summary</th>
<td>__has_c_attribute in C++ mode
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>unspecified
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>Windows NT
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>aaron@aaronballman.com
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<p>
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<pre>Currently, __has_c_attribute is a defined macro in C++ mode and responds with
nonzero values for attributes known to C++.
e.g.,
// In C++ mode
#if defined(__has_c_attribute)
#error "ugh" // This error triggers
#endif
// In C mode
#if defined(__has_cpp_attribute)
#error "ugh" // This error does not trigger
#endif
As shown in: <a href="https://godbolt.org/z/KnyQ2G">https://godbolt.org/z/KnyQ2G</a>
Additionally, it seems like the behavior of C-only attribute testing is broken,
even in C mode:
#if __has_c_attribute(clang::transparent_union)
#error "ugh" // This does not trigger, even in C mode
#endif
As shown in: <a href="https://godbolt.org/z/8eHs8R">https://godbolt.org/z/8eHs8R</a></pre>
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