如何求解体系结构x86_64的未定义符号

我试图编译我的类，我得到以下结果。

g++ test.cpp -lconfig++ -stdlib=libstdc++
Undefined symbols for architecture x86_64:
  "CommandParser::parseCommand(std::string)", referenced from:
      _main in test-8f6e3f.o
  "CommandParser::CommandParser()", referenced from:
      _main in test-8f6e3f.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

这是我要编译的类:

#include "commandparser.h"
using namespace libconfig;
CommandParser::CommandParser(string configFile){
  this->configFile = configFile;
}

CommandParser::CommandParser(){
  this->configFile = CONFIG_FILE_NAME;
}
string CommandParser::parseCommand(string cmd){
  Config cfg;
  try{
    cfg.readFile(this->configFile.c_str());
  }
  catch (const FileIOException &fi){
    cerr << "I/O error while reading file." << std::endl;
    exit(1);
  }
  catch (const ParseException &pe){
    cerr << "Parse error at " << pe.getFile() << ":" << pe.getLine()
              << " - " << pe.getError() << endl;
    exit(1);
  }
  try{
    string path = cfg.lookup(cmd);
    cout << "The path to the script is: " << path << endl;
    return path;
  }
  catch(const SettingNotFoundException &e){
    cerr << "No command with the name '"<<cmd<<"'"<<endl;
    exit(1);
  }
}

我怎么能解决这个问题，让代码编译?我用的是Mac OSX 10.9。