<html>
<head>
<base href="https://llvm.org/bugs/" />
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - shared_ptr of function type"
href="https://llvm.org/bugs/show_bug.cgi?id=27566">27566</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>shared_ptr of function type
</td>
</tr>
<tr>
<th>Product</th>
<td>libc++
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</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>All Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>kaballo86@hotmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following snippet triggers a compilation error:
#include <memory>
struct Foo {};
using FooFn = Foo ();
using FooFnPtr = Foo (*)();
using FooDel = void (*)(FooFnPtr);
static_assert(std::is_same<FooFn*, FooFnPtr>::value, "");
void del(FooFnPtr) {}
Foo fun() { return {}; }
int main() {
std::shared_ptr<FooFn>(&fun, &del);
}
The error happens when `std::shared_ptr<Foo ()>` attempts to instantiate
`std::allocator<Foo ()>` in a constructor that does not need that allocator:
<span class="quote">> In file included from prog.cc:1:
> /usr/local/libcxx-head/include/c++/v1/memory:1726:45: error: multiple overloads of 'address' instantiate to the same signature 'const_pointer (const_reference) const noexcept' (aka 'Foo (*(Foo (&)()) const noexcept)()')
> _LIBCPP_INLINE_VISIBILITY const_pointer address(const_reference __x) const _NOEXCEPT
> ^
> /usr/local/libcxx-head/include/c++/v1/memory:4185:44: note: in instantiation of template class 'std::__1::allocator<Foo ()>' requested here
> __cntrl_ = new _CntrlBlk(__p, __d, allocator<_Yp>());
> ^
> prog.cc:13:5: note: in instantiation of function template specialization 'std::__1::shared_ptr<Foo ()>::shared_ptr<Foo (), void (*)(Foo (*)())>' requested here
> std::shared_ptr<FooFn>(&fun, &del);
> ^</span >
The original use case leverages `std::shared_ptr` to bundle a dynamically
loaded function together with a deleter that unloads the dynamic library when
the function is no longer referenced. It is unclear whether this use case is
supported, but I did not spot anything in the standard that would forbid it.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>