C++ 用一个元素初始化向量是否需要复制构造函数？

下面的示例符合clang，但在GCC中失败

代码：

#包括
结构Foo
{
Foo（）=默认值；
Foo（Foo&&）=默认值；
};
Foo-baz（标准：：矢量foos）；
Foo bar1（Foo&&Foo_）
{
std:：vector foos{std:：move（foo_）}；
返回baz（std：：move（foos））；
}
Foo-bar2（Foo&&Foo_）
{
std：：矢量foos；
foos.push_back（标准：：move（foo_））；
返回baz（std：：move（foos））；
}
模板
Foo bar3（Foo&&Foo_，Foos&&Foos_）
{
std:：vector foos{std:：move（foo_），std:：forward（foos_）…}；
返回baz（std：：move（foos））；
}
虚设（）
{
Foo-f1，f2；
bar3（标准移动（f1），标准移动（f2））；
}

错误：

In file included from /opt/gcc-4.9.0/include/c++/4.9.0/vector:62:0,

from /tmp/gcc-explorer-compiler11512-1-c5m2m1/example.cpp:1:

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_construct.h: In instantiation of 'void std::_Construct(_T1*, _Args&& ...) [with _T1 = Foo; _Args = {const Foo&}]':

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:75:53: required from 'static _ForwardIterator std::__uninitialized_copy<_TrivialValueTypes>::__uninit_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = const Foo*; _ForwardIterator = Foo*; bool _TrivialValueTypes = false]'

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:125:41: required from '_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = const Foo*; _ForwardIterator = Foo*]'

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:278:63: required from '_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>&) [with _InputIterator = const Foo*; _ForwardIterator = Foo*; _Tp = Foo]'

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_vector.h:1286:27: required from 'void std::vector<_Tp, _Alloc>::_M_range_initialize(_ForwardIterator, _ForwardIterator, std::forward_iterator_tag) [with _ForwardIterator = const Foo*; _Tp = Foo; _Alloc = std::allocator<Foo>]'

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_vector.h:378:36: required from 'std::vector<_Tp, _Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp = Foo; _Alloc = std::allocator<Foo>; std::vector<_Tp, _Alloc>::allocator_type = std::allocator<Foo>]'

13 : required from here

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_construct.h:75:7: error: use of deleted function 'constexpr Foo::Foo(const Foo&)'

{ ::new(static_cast<void*>(__p)) _T1(std::forward<_Args>(__args)...); }

^

3 : note: 'constexpr Foo::Foo(const Foo&)' is implicitly declared as deleted because 'Foo' declares a move constructor or move assignment operator

struct Foo

^

Compilation failed

在/opt/gcc-4.9.0/include/c++/4.9.0/vector:62:0中包含的文件中，
来自/tmp/gcc-explorer-compiler11512-1-c5m2m1/example.cpp:1：
/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_-construct.h:void std:：_-construct（_-T1*，_-Args&&&…[with _-T1=Foo；_-Args={const-Foo&}]的实例化：
/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:75:53:从“静态”转发迭代器std:：_uninitialized_copy:：_uninitialized_copy（_inputierator，_inputierator，_ForwardIterator）[带_inputierator=const Foo*；_ForwardIterator=Foo*；bool _tinalivaluetypes=false]
/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:125:41:从“_forwarditeratorstd:：uninitialized_copy”（_InputIterator，_InputIterator，_ForwardIterator，_ForwardIterator）[带_InputIterator=const Foo*；_ForwardIterator=Foo*]中需要
/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:278:63:从“_forwarditeratorstd:：：_uninitialized_copy_a”（_inputierator，_inputierator，_ForwardIterator，std:：allocator&）[带_inputierator=const Foo*；_ForwardIterator=Foo*；_Tp=Foo]）
/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_vector.h:1286:27:来自“void std:：vector:：：_M_range_initialize（_ForwardIterator，_ForwardIterator，std:：forward_iterator_标记）[带_ForwardIterator=const Foo*；_Tp=Foo；_Alloc=std:：alloctor]'
/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_vector.h:378:36:std:：vector:：vector（std:：initializer_list，const allocator_type&）中的必填项[withTp=Foo；Alloc=std:：allocator；std:：vector:：allocatortype=std:：allocator]
13：从这里开始需要
/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_construct.h:75:7：错误：使用已删除的函数“constexpr Foo:：Foo（const Foo&）”
{：：新建（静态_-cast（u-p））_-T1（标准：：转发（u-args））；}
^
3：注意：“constexpr Foo:：Foo（const Foo&）”隐式声明为已删除，因为“Foo”声明了移动构造函数或移动赋值运算符
结构Foo
^
编译失败

---

如果它是GCC中的一个bug，有人能为

bar3

函数提供一个简单的解决方法吗？

不可能从

初始值设定项列表中移出，因此
std:：vector
的相应构造函数必须复制。这就是为什么你会犯错误<代码>bar2

应无错误地编译

---

重复调用

push_back

的常规模板包扩展技巧应该适用于可变版本。

我无法复制粘贴此处的代码

我无法访问您发布的站点。@balki，clang++没有在我的平台上编译：

。。。复制构造函数被隐式删除，因为“Foo”有一个用户声明的移动构造函数…

@Hamidi感谢您编辑此问题，除了所请求的解决方法外，这已在中介绍。它按其应该的方式失败。

In file included from /opt/gcc-4.9.0/include/c++/4.9.0/vector:62:0,

from /tmp/gcc-explorer-compiler11512-1-c5m2m1/example.cpp:1:

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_construct.h: In instantiation of 'void std::_Construct(_T1*, _Args&& ...) [with _T1 = Foo; _Args = {const Foo&}]':

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:75:53: required from 'static _ForwardIterator std::__uninitialized_copy<_TrivialValueTypes>::__uninit_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = const Foo*; _ForwardIterator = Foo*; bool _TrivialValueTypes = false]'

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:125:41: required from '_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = const Foo*; _ForwardIterator = Foo*]'

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_uninitialized.h:278:63: required from '_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>&) [with _InputIterator = const Foo*; _ForwardIterator = Foo*; _Tp = Foo]'

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_vector.h:1286:27: required from 'void std::vector<_Tp, _Alloc>::_M_range_initialize(_ForwardIterator, _ForwardIterator, std::forward_iterator_tag) [with _ForwardIterator = const Foo*; _Tp = Foo; _Alloc = std::allocator<Foo>]'

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_vector.h:378:36: required from 'std::vector<_Tp, _Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp = Foo; _Alloc = std::allocator<Foo>; std::vector<_Tp, _Alloc>::allocator_type = std::allocator<Foo>]'

13 : required from here

/opt/gcc-4.9.0/include/c++/4.9.0/bits/stl_construct.h:75:7: error: use of deleted function 'constexpr Foo::Foo(const Foo&)'

{ ::new(static_cast<void*>(__p)) _T1(std::forward<_Args>(__args)...); }

^

3 : note: 'constexpr Foo::Foo(const Foo&)' is implicitly declared as deleted because 'Foo' declares a move constructor or move assignment operator

struct Foo

^

Compilation failed