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I found examples and posts to

  • Create a static C++ lib for use in a C++ application
  • Create a static Objective C lib for use in an Objective C app.

What I couldn't find and have hassled around with for days now, is the correct way to create a static C++ lib for use in a Objective-C app under XCode 4.

I just want to use this very simple code for testing purposes:

#include <iostream> #include "myCppLib.h" using namespace std; extern "C" void show_the_world() { cout << "Hello, world!\n"; }

I compile this with armv6/armv7 target, GCC 4.2 compiler, Linking 'C++ Standard Library Type' as 'Static' and have "Symbols Hidden by Default" to YES, as described by the Xcode help for static C++ libs.

My Objective-C app which calls the 'show_the_world' function errors about the std++ lib, which seems not to be included or not correctly referenced:

Undefined symbols for architecture armv6: "std::ios_base::Init::~Init()", referenced from: ___tcf_0 in libmyCppLib_dev.a(myCppLib.o) "std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from: _show_the_world in libmyCppLib_dev.a(myCppLib.o) "std::ios_base::Init::Init()", referenced from: __static_initialization_and_destruction_0(int, int)in libmyCppLib_dev.a(myCppLib.o) "std::cout", referenced from: _show_the_world in libmyCppLib_dev.a(myCppLib.o) ld: symbol(s) not found for architecture armv6 collect2: ld returned 1 exit status

I am sure that I compiled the library for the right architecture, so there must be something wrong in another setting or with my code.

Any help is welcome!

Best regards, jimmy

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  • This thread may help - stackoverflow.com/questions/376966/…. Commented Jul 30, 2011 at 12:13
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    I already new this post, but because of my 'not so good' english, I did not found the answer in this post. After you redirected me back to this, I took myself a little more time - and now it works :) the point was to include the std++ lib into the compiling of the resulting objective-c project, too. So, thanks a lot! Commented Aug 9, 2011 at 13:38
  • yeah, libstdc++.dylib solves the problem, amazing! Commented Apr 8, 2012 at 13:05

2 Answers 2

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The correct answer was provided by Jimmy Koerting in the comments: the app needs to be linked against libstdc++.dylib to resolve the standard library symbols. Thanks to Jimmy Koerting, but one more thing i want to add here is, if you are using xcode latest version with iOS 6.1 please add this libstdc++.6.dylib

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Yes, on my Xcode 5.0.2 I had to use libstdc++.6.dylib to resolve the linker errors. Using libstdc++.dylib or libc++.dylib did not help.
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Answered in my own comment ;)

the point was to include the std++ lib into the compiling of the resulting objective-c project, too.

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