Can't bind method to tr1 function with no arguments

[Tron Thomas]

The following contains a snippet of code I representative of service provider I'm trying to implement:

#include <string>
#include <tr1/functional>

class Service
{
public:
    virtual ~Service(){}
};

class ServiceProvider
{
public:
    typedef std::tr1::function<Service* ()> InvokeMethod;

    static void Register(const std::string&, InvokeMethod)
    {
        // maps string to method ...
    }
};

class MockTestService : public Service
{
public:
    MockTestService()
    {
        ServiceProvider::Register("MockTestService",
            std::tr1::bind(&MockTestService::GetService, this,
                std::tr1::placeholders::_1));
    }
    
private:
    Service* GetService()
    {
        return this;
    }
};

When I try to compile this code on Mac OS X 10.6 using version4.2.1 of the GNU compiler, I get a lengthy error message:

/usr/include/c++/4.2.1/tr1/bind_iterate.h: In member function ‘typename std::tr1::result_of<_Functor ()(typename std::tr1::result_of<std::tr1::_Mu<_T1, std::tr1::is_bind_expression<_T1>::value, (std::tr1::is_placeholder<_T1>::value > 0)> ()(_T1, std::tr1::tuple<std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass>)>::type, typename std::tr1::result_of<std::tr1::_Mu<_T1, std::tr1::is_bind_expression<_T1>::value, (std::tr1::is_placeholder<_T1>::value > 0)> ()(_T2, std::tr1::tuple<std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass>)>::type)>::type std::tr1::_Bind<_Functor ()(_T1, _T2)>::operator()() [with _Functor = std::tr1::_Mem_fn<Service* (MockTestService::*)()>, _T1 = MockTestService*, _T2 = std::tr1::_Placeholder<1>]’:
/usr/include/c++/4.2.1/tr1/functional_iterate.h:488:   instantiated from ‘static _Res std::tr1::_Function_handler<_Res ()(), _Functor>::_M_invoke(const std::tr1::_Any_data&) [with _Res = Service*, _Functor = std::tr1::_Bind<std::tr1::_Mem_fn<Service* (MockTestService::*)()> ()(MockTestService*, std::tr1::_Placeholder<1>)>]’
/usr/include/c++/4.2.1/tr1/functional_iterate.h:847:   instantiated from ‘std::tr1::function<_Res ()()>::function(_Functor, typename __gnu_cxx::__enable_if<(! std::tr1::is_integral<_Functor>::value), std::tr1::function<_Res ()()>::_Useless>::__type) [with _Functor = std::tr1::_Bind<std::tr1::_Mem_fn<Service* (MockTestService::*)()> ()(MockTestService*, std::tr1::_Placeholder<1>)>, _Res = Service*]’
ServiceProvider.cpp:28:   instantiated from here
/usr/include/c++/4.2.1/tr1/bind_iterate.h:45: error: no match for call to ‘(std::tr1::_Mem_fn<Service* (MockTestService::*)()>) (MockTestService*&, std::tr1::_NullClass&)’
/usr/include/c++/4.2.1/tr1/functional_iterate.h:207: note: candidates are: _Res std::tr1::_Mem_fn<_Res (_Class::*)()>::operator()(_Class&) const [with _Res = Service*, _Class = MockTestService]
/usr/include/c++/4.2.1/tr1/functional_iterate.h:213: note:                 _Res std::tr1::_Mem_fn<_Res (_Class::*)()>::operator()(_Class*) const [with _Res = Service*, _Class = MockTestService]
...

If I change the typedef of ServiceProvider::InvokeMethod to something like:
typedef std::tr1::function<Service* (void*)> InvokeMethod;
and make a simpilar change to the signature of MockTestService::GetService like:
Service MockTestService::GetService(void*);
the code compiles just fine.

How can I get the code to compile successfully without requiring any arguments for the callback type?

[jsmith]

remove the std::tr1::placeholders::_1 from line 28. You're telling it that GetService should be passed one argument
to be determined at the point of invocation, but your InvokeMethod expects zero parameters.