Boost's thread group on Xcode

I was trying to run a small test program on Xcode (4.2) using C++ after encountering error in my project. ``` #include <boost/thread.hpp> #include <boost/bind.hpp> int main (int argc, const char * argv[]) { boost::thread_group tg; return 0; } ``` But the whole program fails to build, outputting error: ``` Undefined symbols for architecture x86_64: "boost::thread::~thread()", referenced from: boost::thread_group::~thread_group()in main.o ld: symbol(s) not found for architecture x86_64 collect2: ld returned 1 exit status ``` Then I tried using ``` thread_group * tg = new thread_group(); ``` which compiles without issue, up until I tried to invoke ``` tg->join_all(); ``` where the compiler outputs errors such as: ``` Undefined symbols for architecture x86_64: "boost::detail::get_current_thread_data()", referenced from: boost::detail::interruption_checker::interruption_checker(_opaque_pthread_mutex_t*, _opaque_pthread_cond_t*)in main.o "boost::this_thread::interruption_point()", referenced from: boost::condition_variable::wait(boost::unique_lock<boost::mutex>&) in main.o "boost::this_thread::disable_interruption::disable_interruption()", referenced from: boost::shared_mutex::lock_shared() in main.o "boost::this_thread::disable_interruption::~disable_interruption()", referenced from: boost::shared_mutex::lock_shared() in main.o "boost::thread::join()", referenced from: boost::thread_group::join_all() in main.o ld: symbol(s) not found for architecture x86_64 collect2: ld returned 1 exit status ``` Does anyone know how to resolve these issues ? I've been using other functions such as BOOST_FOREACH without any issues. But encounter these while trying to use threads. Do I need to: - Specify flags on my 'Other Linker Flags'? - reinstall boost or some sort ? Currently I am using Boost 1.49.0, installed using homebrew (i.e. sudo brew install boost) Or are there any other specific configurations that I need to to include ?