xcode libstdc++ 已弃用；移至 libc++ [-Wdeprecated] 但更改会产生编译错误

libstdc++ is deprecated; move to libc++ [-Wdeprecated] BUT Changing produces compile error

提问by Reimond Hill

I am working on a project that implements OhNet Library. It also gives you the opportunity og using The project was started when I joined the team and they gave the compiled library and the implementation. After redoing some classes and Clearing all the warning, the last one I have is "libstdc++ is deprecated; move to libc++ [-Wdeprecated]". I hope that by changing to the suggested choice the warning would go away BUT I get a bunch off compiling errors

我正在开发一个实现 OhNet 库的项目。它还为您提供了机会 og 使用该项目是在我加入团队时启动的，他们提供了已编译的库和实现。在重做一些类并清除所有警告后，我的最后一个是“不推荐使用 libstdc++；移至 libc++ [-Wdeprecated]”。我希望通过更改为建议的选择警告会消失但我得到了一堆编译错误

Undefined symbols for architecture arm64:
  "std::_List_node_base::unhook()", referenced from:
      OpenHome::Net::CpiSubscriptionManager::Run() in libohNetCore.a(CpiSubscription.o)
      OpenHome::Net::DviSubscriptionManager::Run() in libohNetCore.a(DviSubscription.o)
      OpenHome::Net::CpiDeviceListUpdater::~CpiDeviceListUpdater() in libohNetCore.a(CpiDevice.o)
      OpenHome::Net::CpiDeviceListUpdater::Run() in libohNetCore.a(CpiDevice.o)
      OpenHome::NetworkAdapterChangeNotifier::~NetworkAdapterChangeNotifier() in libohNetCore.a(NetworkAdapterList.o)
      OpenHome::NetworkAdapterChangeNotifier::Run() in libohNetCore.a(NetworkAdapterList.o)
      OpenHome::Net::XmlFetchManager::~XmlFetchManager() in libohNetCore.a(XmlFetcher.o)
      ...
  "std::__throw_length_error(char const*)", referenced from:
      std::vector<OpenHome::Net::Argument*, std::allocator<OpenHome::Net::Argument*> >::_M_insert_aux(__gnu_cxx::__normal_iterator<OpenHome::Net::Argument**, std::vector<OpenHome::Net::Argument*, std::allocator<OpenHome::Net::Argument*> > >, OpenHome::Net::Argument* const&) in libohNetCore.a(CpiService.o)
      std::vector<OpenHome::Net::DvAction, std::allocator<OpenHome::Net::DvAction> >::_M_insert_aux(__gnu_cxx::__normal_iterator<OpenHome::Net::DvAction*, std::vector<OpenHome::Net::DvAction, std::allocator<OpenHome::Net::DvAction> > >, OpenHome::Net::DvAction const&) in libohNetCore.a(DviService.o)
      std::vector<OpenHome::Net::Property*, std::allocator<OpenHome::Net::Property*> >::_M_insert_aux(__gnu_cxx::__normal_iterator<OpenHome::Net::Property**, std::vector<OpenHome::Net::Property*, std::allocator<OpenHome::Net::Property*> > >, OpenHome::Net::Property* const&) in libohNetCore.a(DviService.o)
      std::vector<OpenHome::Net::DviSubscription*, std::allocator<OpenHome::Net::DviSubscription*> >::_M_insert_aux(__gnu_cxx::__normal_iterator<OpenHome::Net::DviSubscription**, std::vector<OpenHome::Net::DviSubscription*, std::allocator<OpenHome::Net::DviSubscription*> > >, OpenHome::Net::DviSubscription* const&) in libohNetCore.a(DviService.o)
      std::vector<OpenHome::Net::Parameter*, std::allocator<OpenHome::Net::Parameter*> >::_M_insert_aux(__gnu_cxx::__normal_iterator<OpenHome::Net::Parameter**, std::vector<OpenHome::Net::Parameter*, std::allocator<OpenHome::Net::Parameter*> > >, OpenHome::Net::Parameter* const&) in libohNetCore.a(Service.o)
      std::vector<OpenHome::MListener*, std::allocator<OpenHome::MListener*> >::_M_insert_aux(__gnu_cxx::__normal_iterator<OpenHome::MListener**, std::vector<OpenHome::MListener*, std::allocator<OpenHome::MListener*> > >, OpenHome::MListener* const&) in libohNetCore.a(Env.o)
      std::vector<OpenHome::ISuspendObserver*, std::allocator<OpenHome::ISuspendObserver*> >::_M_insert_aux(__gnu_cxx::__normal_iterator<OpenHome::ISuspendObserver**, std::vector<OpenHome::ISuspendObserver*, std::allocator<OpenHome::ISuspendObserver*> > >, OpenHome::ISuspendObserver* const&) in libohNetCore.a(Env.o)

I am using "libohNetCore.a" and "libohNetProxies.a"

我正在使用“ libohNetCore.a”和“ libohNetProxies.a”

Why am I getting this errors? What is exactly this change doing?

为什么我会收到此错误？这种变化到底在做什么？

Thank you very much.

非常感谢。

采纳答案by Petesh

You can't use the already compiled .afiles when you change to a different implementation of the C++standard libraries.

.a当您更改为C++标准库的不同实现时，您不能使用已编译的文件。

These libraries appear to have been compiled with libstdc++, and as such expose methods that will only work with libstdc++. You would need copies of libohNetCore.aand libohNetProxies.athat were compiled with libc++in order to have them work when you switch to libc++.

这些库似乎是用 编译的libstdc++，因此公开仅适用于libstdc++. 你需要的副本libohNetCore.a，并libohNetProxies.a认为用汇编libc++，以便让他们的工作，当你切换到libc++。

I downloaded the OhNetcode from github. It's defined to support -miphoneos-version-min=2.2so it will compile with libstdc++, as it will be built to support iOS 2.2 and newer.

我OhNet从 github下载了代码。它被定义为支持，-miphoneos-version-min=2.2因此它将使用 编译libstdc++，因为它将被构建为支持 iOS 2.2 和更新版本。

If you change the minimum targeted iOS to 5.0, then you can add -stdlib=libc++to the compile line:

如果将最小目标 iOS 更改为5.0，则可以添加-stdlib=libc++到编译行：

compiler = $(toolroot)/clang -stdlib=libc++

and it will compile with libc++.

它将与libc++.

If you change the minimum targeted iOS to 7.0then it will compile with libc++by default, and once you've compiled you will have the libOhNetCore.acompiled for libc++.

如果您将最小目标 iOS 更改为默认情况下7.0它将编译libc++，并且一旦您编译，您将libOhNetCore.a编译为libc++.

To check if a .ais compiled for libstdc++ or libc++, you need to run an nm on it looking for, for example, std::string e.g.

要检查 a.a是否为 libstdc++ 或 libc++ 编译，您需要在其上运行 nm 以查找例如 std::string eg

$ nm ./Build/Obj/iOS-arm64/Release/libohNetCore.a | c++filt | grep std::string | head -1
0000000000000084 T OpenHome::Net::CpDeviceCpp::GetAttribute(char const*, std::string&) const

This is compiled with libstdc++- the presence of std::stringindicates this.

这是编译的libstdc++- 的存在std::string表明这一点。

for libc++, the pattern is slightly different:

对于 libc++，模式略有不同：

$ nm ./Build/Obj/iOS-arm64/Release/libohNetCore.a | c++filt | grep string | head -1
0000000000000084 T OpenHome::Net::CpDeviceCpp::GetAttribute(char const*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&) const

i.e. the presence of std::__1indicates that it's compiled with libc++.

即存在std::__1表明它是用libc++.