http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55123
Bug #: 55123
Summary: [C++11] Construction of shared_ptr<const T> from
unique_ptr<const T> fails
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: yegor.dereven...@gmail.com
Hello,
construction of a shared_ptr from a unique_ptr to a const object seems not to
work, although it should. Preprocessed file is attached.
[yegor@tomato tmp]$ cat test.cpp
#include <memory>
void f() {
std::unique_ptr<const int> y;
std::shared_ptr<const int> x = std::move(y);
}
[yegor@tomato tmp]$ g++ -c -std=c++11 -save-temps test.cpp
In file included from
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/x86_64-unknown-linux-gnu/bits/c++allocator.h:34:0,
from
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/bits/allocator.h:48,
from
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/memory:65,
from test.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/ext/new_allocator.h:
In instantiation of ‘struct __gnu_cxx::new_allocator<const int>’:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/bits/allocator.h:89:11:
required from ‘class std::allocator<const int>’
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/bits/shared_ptr_base.h:329:14:
required from ‘struct std::_Sp_counted_deleter<const int*,
std::default_delete<const int>, std::allocator<const int>,
(__gnu_cxx::_Lock_policy)2u>::_My_Deleter’
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/bits/shared_ptr_base.h:374:24:
required from ‘class std::_Sp_counted_deleter<const int*,
std::default_delete<const int>, std::allocator<const int>,
(__gnu_cxx::_Lock_policy)2u>’
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/bits/shared_ptr_base.h:625:39:
required from ‘static std::_Sp_counted_base<_Lp>*
std::__shared_count<_Lp>::_S_create_from_up(std::unique_ptr<_Up, _Ep>&&,
typename std::enable_if<(! std::is_reference<_Del>::value)>::type*) [with _Tp =
const int; _Del = std::default_delete<const int>; __gnu_cxx::_Lock_policy _Lp =
(__gnu_cxx::_Lock_policy)2u; typename std::enable_if<(!
std::is_reference<_Del>::value)>::type = void]’
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/bits/shared_ptr_base.h:549:43:
required from ‘std::__shared_count<_Lp>::__shared_count(std::unique_ptr<_Up,
_Ep>&&) [with _Tp = const int; _Del = std::default_delete<const int>;
__gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2u]’
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/bits/shared_ptr_base.h:855:4:
required from ‘std::__shared_ptr<_Tp, _Lp>::__shared_ptr(std::unique_ptr<_Up,
_Ep>&&) [with _Tp1 = const int; _Del = std::default_delete<const int>; _Tp =
const int; __gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2u]’
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/bits/shared_ptr.h:259:36:
required from ‘std::shared_ptr<_Tp>::shared_ptr(std::unique_ptr<_Up, _Ep>&&)
[with _Tp1 = const int; _Del = std::default_delete<const int>; _Tp = const
int]’
test.cpp:5:44: required from here
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/ext/new_allocator.h:83:7:
error: ‘const _Tp*
__gnu_cxx::new_allocator<_Tp>::address(__gnu_cxx::new_allocator<_Tp>::const_reference)
const [with _Tp = const int; __gnu_cxx::new_allocator<_Tp>::const_pointer =
const int*; __gnu_cxx::new_allocator<_Tp>::const_reference = const int&]’
cannot be overloaded
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../include/c++/4.7.2/ext/new_allocator.h:79:7:
error: with ‘_Tp*
__gnu_cxx::new_allocator<_Tp>::address(__gnu_cxx::new_allocator<_Tp>::reference)
const [with _Tp = const int; __gnu_cxx::new_allocator<_Tp>::pointer = const
int*; __gnu_cxx::new_allocator<_Tp>::reference = const int&]’
[yegor@tomato tmp]$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /build/src/gcc-4.7.2/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch
--enable-libstdcxx-time --enable-gnu-unique-object --enable-linker-build-id
--with-ppl --enable-cloog-backend=isl --disable-ppl-version-check
--disable-cloog-version-check --enable-lto --enable-gold --enable-ld=default
--enable-plugin --with-plugin-ld=ld.gold --with-linker-hash-style=gnu
--enable-multilib --disable-libssp --disable-build-with-cxx
--disable-build-poststage1-with-cxx --enable-checking=release
Thread model: posix
gcc version 4.7.2 (GCC)
