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<head>
<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 --- - clang rejects valid C++ code with variable argument function"
href="https://llvm.org/bugs/show_bug.cgi?id=31002">31002</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>clang rejects valid C++ code with variable argument function
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</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++
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>su@cs.ucdavis.edu
</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>It seems to affect all clang versions since at least as early as 3.2.x, and is
also incorrectly rejected by ICC.
Both GCC and MSVC correctly accept the code.
The code is accepted if the destructor is commented out.
$ clang++ -v
clang version 4.0.0 (trunk 286715)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/clang-trunk/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.0.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$
$ g++-6.2 small.cpp
$
$ clang++ small.cpp
small.cpp:12:20: error: second argument to 'va_arg' is of non-POD type 'A'
[-Wnon-pod-varargs]
A v = va_arg (a, A);
^
/usr/local/clang-trunk/bin/../lib/clang/4.0.0/include/stdarg.h:35:50: note:
expanded from macro 'va_arg'
#define va_arg(ap, type) __builtin_va_arg(ap, type)
^~~~
small.cpp:19:11: error: cannot pass object of non-POD type 'A' through variadic
function; call will abort at runtime
[-Wnon-pod-varargs]
foo (t, t);
^
2 errors generated.
$
----------------------------
#include <cstdarg>
struct A
{
virtual ~A () {}
};
void foo (A p, ...)
{
va_list a;
va_start (a, p);
A v = va_arg (a, A);
va_end (a);
}
int main ()
{
A t;
foo (t, t);
return 0;
}</pre>
</div>
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