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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Provide a way to check for RAII temporaries"
href="http://llvm.org/bugs/show_bug.cgi?id=17234">17234</a>
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<th>Summary</th>
<td>Provide a way to check for RAII temporaries
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>benny.kra@gmail.com
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</tr>
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<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
</td>
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<p>
<div>
<pre>Take this example of a scoped RAII lock
void mutex_lock(int);
void mutex_unlock();
struct ScopedLock {
__attribute__((warn_unused_result)) ScopedLock(int i) { mutex_lock(i); }
~ScopedLock() { mutex_unlock(); }
};
int main() {
{
ScopedLock(42);
// Does not do what you might think.
// more code ...
}
}
The lock is immediately destroyed and does nothing, which is a typo. I tried to
add a warning here with the warn_unused_result attribute but clang only returns
a poorly worded warning:
warning: attribute 'warn_unused_result' cannot be applied to functions without
return value
It would be nice to have a way to warn on constructs like this.</pre>
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