xcode下出现Undefined symbols for architecture arm64或者armv7: “_OBJC_CLASS_$_XXX

首先，介绍下Apple LLVM compiler 4.2 与LLVM GCC的区别：

某些项目采用了一些第三方库，有时候可能会因为编译方式的不同导致无法项目编译通过，目前xcode 最新的默认的Compiler for C/C++/Objective C为apple LLVM compiler 4.2, 但其采用的C++ Standard Library 却为libc++(LLVM C++ standard libraryth C++ 11 support)， 有些开源类的第三方库可能会采用 原始的LLVM GCC编译器(c++ 标准库为libstdC++)。而libstdC++
与 libc++(LLVM C++ standard libraryth C++ 11 support) 是有很大区别的，具体的历史渊源可以维基百科等等的查询一下，这里就不详细的讲解了。

解决方式有两种：

1. 选择 apple LLVM compiler 4.2, c++ 标准库改为libstdc++(GNU C++ standard library)

2. 选择LLVM GCC, c++标准库为libstdC++

下面是对应真机的处理器：

armv7 , armv7s对应真机的32位处理器，

arm64对应真机的64位模拟器，

i386对应模拟器的32位模拟器；

x86_64对应模拟器的64位模拟器。

碰到一个类似上述的问题，感觉还是stl的C++库加载造成的问题。

即使通过gcc -v查看了编译过程，

然后用gcc -E 导出了预编译后的文件，

查看到的仍然只是std::string，为什么会出现接口中

有的是fucn(std::string)

有的是func(std::__1::basic_string...)

仍然没有搞清楚，网上有一篇似乎可以处理这个问题的文章，如下：

http://blog.csdn.net/kaizi318/article/details/10362673 

但是尝试后，发现xcode仍然报错。

通过在后台用nm查看调用。

发现如果用libstdc++库，则需要使用指定头文件，添加头文件路径如下：

-I $(shell $(XCRUN) --show-sdk-path)/usr/include/c++/4.2.1

其对应使用的std::string类型就是std::string。

而若是不指定用libstdc++，而是使用默认的libc++库，则使用的是默认的C++头文件，

其对应使用的std::string变成了std::__1::basic_string(........)之类的

因此，c++头文件使用的不同导致其他使用stl的库的函数签名和实现都不同了

参考文章如下：

Undefined symbols for architecture i386或者armv7: “_OBJC_CLASS_$_XXX

Undefined symbols for architecture i386:

“_OBJC_CLASS_$_XXX”,  referen ced from:

objc-class-ref in XXX

ld: symbol(s) not found for architecture i386

clang: error: linker command failed with exit code 1 (use -v to see invocation)

如果真机调试就是 undefined symbols for architecture armv7错误！

发生这种错误通常是project.pbxproj这个文件引起的，尤其在多人合作开发的时候，svn提交不规范可能导致project.pbxproj发生错误，导致文件的引用不在project.pbxproj文件中。

xcode项目import文件会根据project.pbxproj来查找，查找不到文件的引用则会有上述的错误。

解决方法点击工程，在主界面中点击Build Phases，根据提示信息“XXX”来判断缺少什么文件，一般如果缺少自定义的文件，XXX会是缺少的类名，那么就在Complie Sources中加入该文件。如果缺少类库，则在Link Binary With Libraries中加入该类库。

Undefined symbols for architecture i386:

02	"TextureMan::LoadTexture(std::__1::basic_string, std::__1::allocator > const&, int, bool)", referenced from:

03	tolua_gameinterface_TextureMan_loadTexture00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

04	"SoundManager::BgndMusicPlay(std::__1::basic_string, std::__1::allocator > const&, bool)", referenced from:

05	tolua_gameinterface_SoundManager_BgndMusicPlay00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

06	"SoundManager::BgndMusicStop(std::__1::basic_string, std::__1::allocator > const&, bool)", referenced from:

07	tolua_gameinterface_SoundManager_BgndMusicStop00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

08	"Font::LoadFont(std::__1::basic_string, std::__1::allocator > const&)", referenced from:

09	tolua_gameinterface_Font_loadFont00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

10	"System::MakeDocumentPath(std::__1::basic_string, std::__1::allocator > const&) const", referenced from:

11	tolua_gameinterface_System_makeDocumentPath00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

12	"System::MakeResourcePath(std::__1::basic_string, std::__1::allocator > const&) const", referenced from:

13	ExUnit::LogicThread::Run() in libCoreClientiOS.a(logicthread.o)

14	tolua_gameinterface_System_makeResourcePath00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

15	"std::__1::__vector_base_common::__throw_length_error() const", referenced from:

16	void std::__1::vector >::__push_back_slow_path(float const&&&) inlibCoreClientiOS.a(tolua_gameinterface.o)

17	void std::__1::vector, std::__1::allocator > >::__push_back_slow_path const&>(std::__1::basic_string, std::__1::allocator > const&&&) inlibCoreClientiOS.a(tolua_gameinterface.o)

18	void std::__1::vector >::__push_back_slow_path(int const&&&) inlibCoreClientiOS.a(tolua_gameinterface.o)

19	"std::__1::locale::use_facet(std::__1::locale::id&) const", referenced from:

20	std::__1::basic_ostream >& std::__1::endl >(std::__1::basic_ostream >&) inlibCoreClientiOS.a(logicthread.o)

21	"std::__1::ios_base::getloc() const", referenced from:

22	std::__1::basic_ostream >& std::__1::endl >(std::__1::basic_ostream >&) inlibCoreClientiOS.a(logicthread.o)

23	"std::__1::basic_string, std::__1::allocator >::__init(char const*, unsigned long)", referenced from:

24	_l_registercallback in libCoreClientiOS.a(logicthread.o)

25	_luapanic in libCoreClientiOS.a(logicthread.o)

26	ExUnit::LogicThread::Run() in libCoreClientiOS.a(logicthread.o)

27	ExUnit::LogicThread::HandleError() in libCoreClientiOS.a(logicthread.o)

28	ExUnit::LogicThread::CallVA(char const*, char const*, ...) inlibCoreClientiOS.a(logicthread.o)

29	ExUnit::LogicThread::RemoveCallback(char const*) inlibCoreClientiOS.a(logicthread.o)

30	ExUnit::LogicThread::SetCallback(char const*, int) inlibCoreClientiOS.a(logicthread.o)

31

...

32	"std::__1::basic_string, std::__1::allocator >::assign(char const*)", referenced from:

33	System::SetEngineScriptPath(char const*) inlibCoreClientiOS.a(tolua_gameinterface.o)

34	"std::__1::basic_string, std::__1::allocator >::basic_string(std::__1::basic_string, std::__1::allocator > const&)", referenced from:

35	tolua_gameinterface_vector_string___geti00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

36	tolua_gameinterface_vector_string___geti01(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

37	tolua_gameinterface_vector_string__push_back00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

38	void std::__1::vector, std::__1::allocator > >::__push_back_slow_path const&>(std::__1::basic_string, std::__1::allocator > const&&&) inlibCoreClientiOS.a(tolua_gameinterface.o)

39	"std::__1::basic_string, std::__1::allocator >::~basic_string()", referenced from:

40	_l_registercallback in libCoreClientiOS.a(logicthread.o)

41	_luapanic in libCoreClientiOS.a(logicthread.o)

42	ExUnit::LogicThread::Run() in libCoreClientiOS.a(logicthread.o)

43	ExUnit::LogicThread::HandleError() in libCoreClientiOS.a(logicthread.o)

44	ExUnit::LogicThread::CallVA(char const*, char const*, ...) inlibCoreClientiOS.a(logicthread.o)

45	ExUnit::LogicThread::RemoveCallback(char const*) inlibCoreClientiOS.a(logicthread.o)

46	ExUnit::LogicThread::SetCallback(char const*, int) inlibCoreClientiOS.a(logicthread.o)

47

...

48	"std::__1::basic_string, std::__1::allocator >::operator=(std::__1::basic_string, std::__1::allocator > const&)", referenced from:

49	tolua_gameinterface_vector_string___seti00(lua_State*) inlibCoreClientiOS.a(tolua_gameinterface.o)

50	"std::__1::basic_ostream >::put(char)", referenced from:

51	std::__1::basic_ostream >& std::__1::endl >(std::__1::basic_ostream >&) inlibCoreClientiOS.a(logicthread.o)

52	"std::__1::basic_ostream >::flush()", referenced from:

53	std::__1::basic_ostream >& std::__1::endl >(std::__1::basic_ostream >&) inlibCoreClientiOS.a(logicthread.o)

54	"std::__1::basic_ostream >::sentry::sentry(std::__1::basic_ostream >&)", referenced from:

55	std::__1::basic_ostream >& std::__1::operator<<(std::__1::basic_ostream >&, char const*) in libCoreClientiOS.a(logicthread.o)

56	"std::__1::basic_ostream >::sentry::~sentry()", referenced from:

57	std::__1::basic_ostream >& std::__1::operator<<(std::__1::basic_ostream >&, char const*) in libCoreClientiOS.a(logicthread.o)

58	"std::__1::cerr", referenced from:

59	ExUnit::LogicThread::Run() in libCoreClientiOS.a(logicthread.o)

60	ExUnit::LogicThread::ContactTriggered(b2Contact*) inlibCoreClientiOS.a(logicthread.o)

61	ExUnit::LogicThread::SensorTriggered(b2Contact*) inlibCoreClientiOS.a(logicthread.o)

62	"std::__1::ctype::id", referenced from:

63	std::__1::basic_ostream >& std::__1::endl >(std::__1::basic_ostream >&) inlibCoreClientiOS.a(logicthread.o)

64	"std::__1::locale::~locale()", referenced from:

65	std::__1::basic_ostream >& std::__1::endl >(std::__1::basic_ostream >&) inlibCoreClientiOS.a(logicthread.o)

66	"std::__1::ios_base::__set_badbit_and_consider_rethrow()", referenced from:

67	std::__1::basic_ostream >& std::__1::operator<<(std::__1::basic_ostream >&, char const*) in libCoreClientiOS.a(logicthread.o)

68	"std::__1::ios_base::clear(unsigned int)", referenced from:

69	std::__1::basic_ostream >& std::__1::operator<<(std::__1::basic_ostream >&, char const*) in libCoreClientiOS.a(logicthread.o)

70	ld: symbol(s) not found for architecture i386

71	clang: error: linker command failed with exit code 1 (use -v to see invocation)

看着就非常复杂！

有这么多的link STL的错误。

其实，就是你编译静态库的时候使用不同版本的标准库，  C++ Standard Library

那么如何fix掉这个issue呢？看下面这两张图！

如果你这两个在编译静态库和在使用静态库的app中设置的是一样的，应该就可以解决掉这个问题！

事实上，compiler default 足够了。

iOS出现 Undefined symbols for architecture armv7 std::basic_string

今天，使用了第三方一个库，结果，出现，iOS Undefined symbols for architecture armv7 std::basic_string

注意：不是修改Build Setting里面的设置，而是添加一个libstdc++.dylib, 搞定！