boost:: signal library not working_问答_开发者

Whenever I compile a program using boost::signal I get following errors:

/tmp/ccQFaJsy.o: In function `main':
b_vect.cpp:(.text+0xb7): undefined reference to `boost::signals::connection::~connection()'
/tmp/ccQFaJsy.o: In function `boost::signals::detail::slot_base::data_t::~data_t()':
b_vect.cpp:(.text._ZN5boost7signals6detail9slot_base6data_tD1Ev[boost::signals::detail::slot_base::data_t::~data_t()]+0x16): undefined reference to `boost::signals::connection::~connection()'
/tmp/ccQFaJsy.o: In function `boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::signal0(boost::last_value<void> const&, std::less<int> const&)':
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEEC1ERKS2_RKS4_[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::signal0(boost::last_value<void> const&, std::less<int> const&)]+0x51): undefined reference to `boost::signals::detail::signal_base::signal_base(boost::function2<bool, boost::signals::detail::stored_group, boost::signals::detail::stored_group, std::allocator<boost::function_base> > const&, boost::any const&)'
/tmp/ccQFaJsy.o: In function `boost::slot<boost::function0<void, std::allocator<boost::function_base> > >::slot<HelloWorld>(HelloWorld const&)':
b_vect.cpp:(.text._ZN5boost4slotINS_9function0IvSaINS_13function_baseEEEEEC1I10HelloWorldEERKT_[boost::slot<boost::function0<void, std::allocator<boost::function_base> > >::slot<HelloWorld>(HelloWorld const&)]+0xac): undefined reference to `boost::signals::detail::slot_base::create_connection()'
/tmp/ccQFaJsy.o: In function `boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::connect(boost::slot<boost::function0<void, std::allocator<boost::function_base> > > const&, boost::signals::connect_position)':
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEE7connectERKNS_4slotIS8_EENS_7signals16connect_positionE[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::connect(boost::slot<boost::function0<void, std::allocator<boost::function_base> > > const&, boost::signals::connect_position)]+0x9a): undefined reference to `boost::signals::detail::signal_base_impl::connect_slot(boost::any const&, boost::signals::detail::stored_group const&, boost::shared_ptr<boost::signals::detail::slot_base::data_t>, boost::signals::connect_position)'
/tmp/ccQFaJsy.o: In function `void boost::iterator_core_access::increment<boost::signals::detail::named_slot_map_iterator>(boost::signals::detail::named_slot_map_iterator&)':
b_vect.cpp:(.text._ZN5boost20iterator_core_access9incrementINS_7signals6detail23named_slot_map_iteratorEEEvRT_[void boost::iterator_core_access::increment<boost::signals::detail::named_slot_map_iterator>(boost::signals::detail::named_slot_map_iterator&)]+0x11): undefined reference to `boost::signals::detail::named_slot_map_iterator::increment()'
/tmp/ccQFaJsy.o: In function `bool boost::iterator_core_access::equal<boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator>(boost::signals::detail::named_slot_map_iterator const&, boost::signals::detail::named_slot_map_iterator const&, mpl_::bool_<true>)':
b_vect.cpp:(.text._ZN5boost20iterator_core_access5equalINS_7signals6detail23named_slot_map_iteratorES4_EEbRKT_RKT0_N4mpl_5bool_ILb1EEE[bool boost::iterator_core_access::equal<boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator>(boost::signals::detail::named_slot_map_iterator const&, boost::signals::detail::named_slot_map_iterator const&, mpl_::bool_<true>)]+0x19): undefined reference to `boost::signals::detail::named_slot_map_iterator::equal(boost::signals::detail::named_slot_map_iterator const&) const'
/tmp/ccQFaJsy.o: In function `boost::signals::detail::named_slot_map_iterator::reference boost::iterator_core_access::dereference<boost::signals::detail::named_slot_map_iterator>(boost::signals::detail::named_slot_map_iterator const&)':
b_vect.cpp:(.text._ZN5boost20iterator_core_access11dereferenceINS_7signals6detail23named_slot_map_iteratorEEENT_9referenceERKS5_[boost::signals::detail::named_slot_map_iterator::reference boost::iterator_core_access::dereference<boost::signals::detail::named_slot_map_iterator>(boost::signals::detail::named_slot_map_iterator const&)]+0x11): undefined reference to `boost::signals::detail::named_slot_map_iterator::dereference() const'
/tmp/ccQFaJsy.o: In function `boost::signals::detail::named_slot_map_iterator std::__find_if<boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable>(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable, std::input_iterator_tag)':
b_vect.cpp:(.text._ZSt9__find_ifIN5boost7signals6detail23named_slot_map_iteratorENS2_11is_callableEET_S5_S5_T0_St18input_iterator_tag[boost::signals::detail::named_slot_map_iterator std::__find_if<boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable>(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable, std::input_iterator_tag)]+0x6d): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
/tmp/ccQFaJsy.o: In function `boost::signals::detail::named_slot_map_iterator std::find_if<boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable>(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable)':
b_vect.cpp:(.text._ZSt7find_ifIN5boost7signals6detail23named_slot_map_iteratorENS2_11is_callableEET_S5_S5_T0_[boost::signals::detail::named_slot_map_iterator std::find_if<boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable>(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable)]+0x2b): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZSt7find_ifIN5boost7signals6detail23named_slot_map_iteratorENS2_11is_callableEET_S5_S5_T0_[boost::signals::detail::named_slot_map_iterator std::find_if开发者_开发知识库<boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable>(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::is_callable)]+0x38): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
/tmp/ccQFaJsy.o: In function `boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::slot_call_iterator(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::optional<boost::signals::detail::unusable>&)':
b_vect.cpp:(.text._ZN5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEEC1ESB_SB_SA_RNS_8optionalINS1_8unusableEEE[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::slot_call_iterator(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::optional<boost::signals::detail::unusable>&)]+0x34): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZN5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEEC1ESB_SB_SA_RNS_8optionalINS1_8unusableEEE[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::slot_call_iterator(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::optional<boost::signals::detail::unusable>&)]+0x45): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
/tmp/ccQFaJsy.o:b_vect.cpp:(.text._ZN5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEEC1ESB_SB_SA_RNS_8optionalINS1_8unusableEEE[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::slot_call_iterator(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::optional<boost::signals::detail::unusable>&)]+0x71): more undefined references to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)' follow
/tmp/ccQFaJsy.o: In function `boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::slot_call_iterator(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::optional<boost::signals::detail::unusable>&)':
b_vect.cpp:(.text._ZN5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEEC1ESB_SB_SA_RNS_8optionalINS1_8unusableEEE[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::slot_call_iterator(boost::signals::detail::named_slot_map_iterator, boost::signals::detail::named_slot_map_iterator, boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::optional<boost::signals::detail::unusable>&)]+0xa6): undefined reference to `boost::signals::detail::named_slot_map_iterator::operator=(boost::signals::detail::named_slot_map_iterator const&)'
/tmp/ccQFaJsy.o: In function `boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::increment()':
b_vect.cpp:(.text._ZN5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE9incrementEv[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::increment()]+0x19): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZN5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE9incrementEv[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::increment()]+0x31): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZN5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE9incrementEv[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::increment()]+0x56): undefined reference to `boost::signals::detail::named_slot_map_iterator::operator=(boost::signals::detail::named_slot_map_iterator const&)'
/tmp/ccQFaJsy.o: In function `boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::equal(boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator> const&) const':
b_vect.cpp:(.text._ZNK5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE5equalERKSC_[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::equal(boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator> const&) const]+0x2c): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZNK5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE5equalERKSC_[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::equal(boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator> const&) const]+0x3c): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZNK5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE5equalERKSC_[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::equal(boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator> const&) const]+0x70): undefined reference to `boost::signals::detail::named_slot_map_iterator::operator=(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZNK5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE5equalERKSC_[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::equal(boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator> const&) const]+0x84): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZNK5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE5equalERKSC_[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::equal(boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator> const&) const]+0x94): undefined reference to `boost::signals::detail::named_slot_map_iterator::named_slot_map_iterator(boost::signals::detail::named_slot_map_iterator const&)'
b_vect.cpp:(.text._ZNK5boost7signals6detail18slot_call_iteratorINS1_11call_bound0IvE6callerINS_9function0IvSaINS_13function_baseEEEEEENS1_23named_slot_map_iteratorEE5equalERKSC_[boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator>::equal(boost::signals::detail::slot_call_iterator<boost::signals::detail::call_bound0<void>::caller<boost::function0<void, std::allocator<boost::function_base> > >, boost::signals::detail::named_slot_map_iterator> const&) const]+0xbf): undefined reference to `boost::signals::detail::named_slot_map_iterator::operator=(boost::signals::detail::named_slot_map_iterator const&)'
/tmp/ccQFaJsy.o: In function `boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::operator()()':
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEEclEv[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::operator()()]+0x22): undefined reference to `boost::signals::detail::call_notification::call_notification(boost::shared_ptr<boost::signals::detail::signal_base_impl> const&)'
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEEclEv[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::operator()()]+0x69): undefined reference to `boost::signals::detail::named_slot_map::end()'
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEEclEv[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::operator()()]+0x85): undefined reference to `boost::signals::detail::named_slot_map::end()'
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEEclEv[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::operator()()]+0xc9): undefined reference to `boost::signals::detail::named_slot_map::end()'
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEEclEv[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::operator()()]+0xe2): undefined reference to `boost::signals::detail::named_slot_map::begin()'
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEEclEv[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::operator()()]+0x141): undefined reference to `boost::signals::detail::call_notification::~call_notification()'
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEEclEv[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::operator()()]+0x184): undefined reference to `boost::signals::detail::call_notification::~call_notification()'
/tmp/ccQFaJsy.o: In function `boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::~signal0()':
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEED1Ev[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::~signal0()]+0x1a): undefined reference to `boost::signals::trackable::~trackable()'
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEED1Ev[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::~signal0()]+0x2b): undefined reference to `boost::signals::detail::signal_base::~signal_base()'
b_vect.cpp:(.text._ZN5boost7signal0IvNS_10last_valueIvEEiSt4lessIiENS_9function0IvSaINS_13function_baseEEEEED1Ev[boost::signal0<void, boost::last_value<void>, int, std::less<int>, boost::function0<void, std::allocator<boost::function_base> > >::~signal0()]+0x46): undefined reference to `boost::signals::detail::signal_base::~signal_base()'
collect2: ld returned 1 exit status

Can someone help me please.

those are errors from the linker. so, the code compiles fine, and all the objetcs are produced, but the linker is telling you that you have used symbols (e.g., functions, class methods) which don't appear in any of the objects or files you're linking. so, you'll have to add the objects or libraries with those symbols to the list of files to be linked. the symbols you want may be in the boost binaries.

This may be a bit late for your answer. After seeing your code in the comments , i thing you are not calling the right library.

#include <boost/signals2.hpp> 
#include <iostream> 

void func1() 
{ 
  std::cout << "Hello world" << std::flush; 
} 

int main() 
{ 
  boost::signals2::signal<void ()> s; 
  s.connect(func1); 
  s(); 
}

you got to include signals2.hpp and not signals(though I am not very sure of it). This works just fine for me.