Mac XCODE build error : Undefined symbols for architecture i386-Collection of common programming errors

Currently I am porting a Linux C++ project into Mac OS X 10.7 The problem I am facing now is below-

    Undefined symbols for architecture i386:
  "MsSipAgent::GetInstance()", referenced from:
      NetworkHandler::Start() in networkhandler.o
  "MsSipAgent::Initialize(std::string, std::string, std::string, std::string, int)", referenced from:
      NetworkHandler::RegisterSip() in networkhandler.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Here MsSipAgent is a library that I give into “Link Binary with libraries”. Most of the functions of MsSipAgent is getting no error, except this two method (1)GetInstance() & (2)Initialize(std::string, std::string, std::string, std::string, int). It also says that undefined symbols for architecture i386. But MsSipAgent library was build with setting MAC 32-bit.

It will be highly appreciated if you can make me understand what is the reason behind it. If you need more info please kindly let me know.

Thanks in advance.

Originally posted 2013-11-27 11:52:33.