Creating an Objective-C++ Static Library in Xcode

Question

So I've developed an engine for the iPhone with which I'd like to build a couple different games. Rather than copy and paste the files for the engine inside of each game's project directory, I'd a way to link to the engine from each game, so if I need to make a change to it I only have to do so once. After reeding around a little bit, it seems like static libraries are the best way to do this on the iPhone.

I created a new project called Skeleton and copied all of my engine files over to it. I used this guide to create a static library, and I imported the library into a project called Chooser. However, when I tried to compile the project, Xcode started complaining about some C++ data structures I included in a file called ControlScene.mm. Here's my build errors:

  "operator delete(void*)", referenced from:


      -[ControlScene dealloc] in libSkeleton.a(ControlScene.o)


      -[ControlScene init] in libSkeleton.a(ControlScene.o)


      __gnu_cxx::new_allocator<operation_t>::deallocate(operation_t*, unsigned long)in libSkeleton.a(ControlScene.o)


      __gnu_cxx::new_allocator<operation_t*>::deallocate(operation_t**, unsigned long)in libSkeleton.a(ControlScene.o)


  "operator new(unsigned long)", referenced from:


      -[ControlScene init] in libSkeleton.a(ControlScene.o)


      __gnu_cxx::new_allocator<operation_t*>::allocate(unsigned long, void const*)in libSkeleton.a(ControlScene.o)


      __gnu_cxx::new_allocator<operation_t>::allocate(unsigned long, void const*)in libSkeleton.a(ControlScene.o)


  "std::__throw_bad_alloc()", referenced from:


      __gnu_cxx::new_allocator<operation_t*>::allocate(unsigned long, void const*)in libSkeleton.a(ControlScene.o)


      __gnu_cxx::new_allocator<operation_t>::allocate(unsigned long, void const*)in libSkeleton.a(ControlScene.o)


  "___cxa_rethrow", referenced from:


      std::_Deque_base<operation_t, std::allocator<operation_t> >::_M_create_nodes(operation_t**, operation_t**)in libSkeleton.a(ControlScene.o)


      std::_Deque_base<operation_t, std::allocator<operation_t> >::_M_initialize_map(unsigned long)in libSkeleton.a(ControlScene.o)


  "___cxa_end_catch", referenced from:


      std::_Deque_base<operation_t, std::allocator<operation_t> >::_M_create_nodes(operation_t**, operation_t**)in libSkeleton.a(ControlScene.o)


      std::_Deque_base<operation_t, std::allocator<operation_t> >::_M_initialize_map(unsigned long)in libSkeleton.a(ControlScene.o)


  "___gxx_personality_v0", referenced from:


      ___gxx_personality_v0$non_lazy_ptr in libSkeleton.a(ControlScene.o)


      ___gxx_personality_v0$non_lazy_ptr in libSkeleton.a(MenuLayer.o)


  "___cxa_begin_catch", referenced from:


      std::_Deque_base<operation_t, std::allocator<operation_t> >::_M_create_nodes(operation_t**, operation_t**)in libSkeleton.a(ControlScene.o)


      std::_Deque_base<operation_t, std::allocator<operation_t> >::_M_initialize_map(unsigned long)in libSkeleton.a(ControlScene.o)


ld: symbol(s) not found


collect2: ld returned 1 exit status

If anybody could offer some insight as to why these problems are occuring, I'd appreciate it.

Answer 1

将“-lstdc ++”设置为Other Linker Flags

Answer 2

The problem is that your library is dynamically linking against libstdc++. As to how to fix it, you should try "-static", "-static-libstdc++", and "-static-libgcc" in various combinations when building your library (not sure which of them are needed, but some combination thereof should make it fully static).

Well, it turns out that you are permitted to dynamically link against libstdc++ on the iPhone, so actually a better solution is to simply put "-lstdc++" in (that is, explicitly link against libstdc++) in your build.

Answer 3

I fixed the problem by going into the build settings for Chooser, searching out "Compile Source As" and selecting Objective-C++. This is probably a dirty solution, but it worked.

Answer 4

I ran into this issue when trying to link a .framework. I've managed to fix it by adding an empty cppstub.mm file as source (to Compile Sources phase)

I guess it must be forcing some sort of C++ compilation when you do this, don't ask me why