Boost undefined reference error with boost::bind overloaded operators

Question

The code in question:

boost::function<bool()> isSpecialWeapon = boost::bind(&WeaponBase::GetType,this) == WeaponType::SPECIAL_WEAPON;

The error I get is something like so:

 undefined reference to `boost::_bi::bind_t<bool, boost::_bi::equal, 
 boost::_bi::list2<boost::_bi::bind_t<WeaponType::Guns, 
 boost::_mfi::cmf0<WeaponType::Guns, WeaponBase>,  
 boost::_bi::list1<boost::_bi::value<WeaponBase*> > >, 
 boost::_bi::add_value<WeaponType::Guns>::type> > boost::_bi::operator==
 <WeaponType::Guns, boost::_mfi::cmf0<WeaponType::Guns, WeaponBase>, 
 boost::_bi::list1<boost::_bi::value<WeaponBase*> >, WeaponType::Guns>
 (boost::_bi::bind_t<WeaponType::Guns, boost::_mfi::cmf0<WeaponType::Guns, WeaponBase>, 
 boost::_bi::list1<boost::_bi::value<WeaponBase*> > > const&, WeaponType::Guns)'

Answer 1

If you can't get boost::bind to work as you desire, you can try Boost.Pheonix or Boost.Lamda as a workaround.

Try using boost::pheonix::bind (from Boost.Pheonix) instead of boost::bind:

#include <boost/phoenix/operator.hpp>
#include <boost/phoenix/bind/bind_member_function.hpp>
#include <boost/function.hpp>
#include <iostream>

enum WeaponType {melee, ranged, special};

class Sword
{
public:
    WeaponType GetType() const {return melee;}

    void test()
    {
        namespace bp = boost::phoenix;
        boost::function<bool()> isSpecialWeapon =
            bp::bind(&Sword::GetType, this) == special;
        std::cout << "isSpecialWeapon() = " << isSpecialWeapon() << "\n";
    }

};

int main()
{
    Sword sword;
    sword.test();
}

---

Alternatively, you also use boost::lambda::bind (from Boost.Lambda):

#include <boost/function.hpp>
#include <boost/lambda/bind.hpp>
#include <boost/lambda/lambda.hpp>
#include <iostream>

enum WeaponType {melee, ranged, special};

class Sword
{
public:
    WeaponType GetType() const {return melee;}

    void test()
    {
        boost::function<bool()> isSpecialWeapon =
            boost::lambda::bind(&Sword::GetType, this) == special;
        std::cout << "isSpecialWeapon() = " << isSpecialWeapon() << "\n";
    }

};

int main()
{
    Sword sword;
    sword.test();
}