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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - compiler warning padding lambda"
href="https://llvm.org/bugs/show_bug.cgi?id=31709">31709</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>compiler warning padding lambda
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Macintosh
</td>
</tr>
<tr>
<th>OS</th>
<td>MacOS X
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>C++11
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>nivek.research@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The clang compiler may warn that lambda's are padded
# clang++ -std=c++11 -stdlib=libc++ -Weverything -Wno-c++98-compat main.cpp
main.cpp:22:13: warning: padding class '(lambda at main.cpp:20:45)' with 4
bytes to align anonymous bit-field [-Wpadded]
document->prepare();
^
1 warning generated.
I believe one no control over how the compiler stores the state for the lambda
so I believe the warning should not be shown.
#include <cstdint>
#include <functional>
class Document {
public:
bool unlock(void) { return true; }
void prepare(void) {}
void perform(void) {}
};
uint32_t GetCurrentEventKeyModifiers(void);
void UnlockDocumentAndCallFunction(Document* const inDocument,
std::function<void(void)> const inFunction);
int main() {
Document* const document = new Document();
uint32_t const modifiers = GetCurrentEventKeyModifiers();
UnlockDocumentAndCallFunction(document, [=]() {
if (modifiers & 1) {
document->prepare();
}
document->perform();
});
delete document;
return 0;
}
uint32_t GetCurrentEventKeyModifiers(void) {
return 1;
}
void UnlockDocumentAndCallFunction(Document* const inDocument,
std::function<void(void)> const inFunction) {
if (inDocument->unlock()) {
inFunction();
}
}</pre>
</div>
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