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| author | Douglas Gregor <dgregor@apple.com> | 2011-09-27 18:58:27 +0000 |
|---|---|---|
| committer | Douglas Gregor <dgregor@apple.com> | 2011-09-27 18:58:27 +0000 |
| commit | fb2a0c5a5e4497847dcdf3d4402b38f321bf89ef (patch) | |
| tree | 069d0fc1769c32e92718ece4ba2392dc217db7dc /www | |
| parent | 8ed3adec26af254dd6df6b34546737045f353670 (diff) | |
| download | clang-fb2a0c5a5e4497847dcdf3d4402b38f321bf89ef.tar.gz clang-fb2a0c5a5e4497847dcdf3d4402b38f321bf89ef.tar.bz2 clang-fb2a0c5a5e4497847dcdf3d4402b38f321bf89ef.tar.xz | |
Document the incompatibility that stems from Clang properly implement
the rule that defines the implicit copy constructor/implicit copy
asssignment operator as deleted when a move constructor or move
assignment operator has been explicitly declared. This has hit a
number of people because Boost 1.47.0's shared_ptr fails to declare a
copy constructor.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140621 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'www')
| -rw-r--r-- | www/compatibility.html | 40 |
1 files changed, 39 insertions, 1 deletions
diff --git a/www/compatibility.html b/www/compatibility.html index 783758f3ac..2102ccca7e 100644 --- a/www/compatibility.html +++ b/www/compatibility.html @@ -60,6 +60,12 @@ <li><a href="#param_name_lookup">Parameter name lookup</a></li> </ul> </li> + <li><a href="#c++11">C++11 compatibility</a> + <ul> + <li><a href="#deleted-special-func">Deleted special member + functions</a></li> + </ul> + </li> <li><a href="#objective-c++">Objective-C++ compatibility</a> <ul> <li><a href="#implicit-downcasts">Implicit downcasts</a></li> @@ -755,7 +761,39 @@ void f(int a, int a); <p>Clang diagnoses this error (where the parameter name has been redeclared). To fix this problem, rename one of the parameters.</p> <!-- ======================================================================= --> -<h2 id="objective-c++">Objective-C++ compatibility</h3> +<h2 id="c++11">C++11 compatibility</h2> +<!-- ======================================================================= --> + +<!-- ======================================================================= --> +<h3 id="deleted-special-func">Deleted special member functions</h3> +<!-- ======================================================================= --> + +<p>In C++11, the explicit declaration of a move constructor or a move +assignment operator within a class disables the implicit declaration +of the copy constructor and copy assignment operator. This change came +fairly late in the C++11 standardization process, so early +implementations of C++11 (including Clang before 3.0, GCC before 4.7, +and Visual Studio 2010) do not implement this rule, leading them to +accept this ill-formed code:</p> + +<pre> +struct X { + X(X&&); <i>// suppresses implicit copy constructor</i> +}; + +void f(X x); +void g(X x) { + f(x); <i>// error: X has no copy constructor</i> +} +</pre> + +<p>This affects some C++11 code, including Boost's popular <a +href="http://www.boost.org/doc/libs/release/libs/smart_ptr/shared_ptr.htm"><tt>shared_ptr</tt></a> +up to version 1.47.0. The fix for Boost's <tt>shared_ptr</tt> is +<a href="https://svn.boost.org/trac/boost/changeset/73202">available here</a>.</p> + +<!-- ======================================================================= --> +<h2 id="objective-c++">Objective-C++ compatibility</h2> <!-- ======================================================================= --> <!-- ======================================================================= --> |