Hi All,

I'm trying to connect a simple void returning function to multiple signals of varying signature, I can see some references mentioning that it's possible using boost::lambda::bind and boost::spirit::bind, But I keep getting compilation errors, Is there something wrong with the following code? Or is there a better way to do it? or is it not possible to do?

Boost version: Release 1.46.1

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#include <boost/signals2.hpp>
#include <boost/lambda/bind.hpp>
#include <boost/lambda/lambda.hpp>
#include <boost/spirit/include/phoenix.hpp>
using namespace boost::signals2;

void func()
{
  printf("Func called!");
}

main()
{
  signal<int(int)> sig;
  sig.connect( (boost::lambda::bind(func),  1) ); // Compilation error
//  sig.connect( (boost::phoenix::bind(func), 1) ); // Compilation error
}


I'm getting the following compilation errors when using boost::lambda::bind:

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/opt/include/boost/signals2/detail/slot_template.hpp: In member function ‘void boost::signals2::slot1<R, T1, SlotFunction>::init_slot_function(const F&) [with F = int, R = int, T1 = int, SlotFunction = boost::function<int(int)>]’:
/opt/include/boost/signals2/detail/slot_template.hpp:81:9:   instantiated from ‘boost::signals2::slot1<R, T1, SlotFunction>::slot1(const F&) [with F = int, R = int, T1 = int, SlotFunction = boost::function<int(int)>]’
hello-world-example.cpp:15:51:   instantiated from here
/opt/include/boost/signals2/detail/slot_template.hpp:156:9: error: invalid conversion from ‘int’ to ‘boost::function<int(int)>::clear_type*’ [-fpermissive]
/opt/include/boost/function/function_template.hpp:1110:14: error:   initializing argument 1 of ‘boost::function<R(T0)>::self_type& boost::function<R(T0)>::operator=(boost::function<R(T0)>::clear_type*) [with R = int, T0 = int, boost::function<R(T0)>::self_type = boost::function<int(int)>]’ [-fpermissive]

I'm getting the following compilation errors when using boost::phoenix::bind:

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/opt/include/boost/function/function_template.hpp: In static member function ‘static R boost::detail::function::function_obj_invoker1<FunctionObj, R, T0>::invoke(boost::detail::function::function_buffer&, T0) [with FunctionObj = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::detail::function_eval<0>, boost::fusion::vector<boost::phoenix::value<boost::phoenix::detail::function_ptr<0, void, void (*)()> >, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >, R = int, T0 = int]’:
/opt/include/boost/function/function_template.hpp:913:60:   instantiated from ‘void boost::function1<R, T1>::assign_to(Functor) [with Functor = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::detail::function_eval<0>, boost::fusion::vector<boost::phoenix::value<boost::phoenix::detail::function_ptr<0, void, void (*)()> >, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >, R = int, T0 = int]’
/opt/include/boost/function/function_template.hpp:722:7:   instantiated from ‘boost::function1<R, T1>::function1(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::detail::function_eval<0>, boost::fusion::vector<boost::phoenix::value<boost::phoenix::detail::function_ptr<0, void, void (*)()> >, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >, R = int, T0 = int, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’
/opt/include/boost/function/function_template.hpp:1064:16:   instantiated from ‘boost::function<R(T0)>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::detail::function_eval<0>, boost::fusion::vector<boost::phoenix::value<boost::phoenix::detail::function_ptr<0, void, void (*)()> >, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >, R = int, T0 = int, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’
/opt/include/boost/function/function_template.hpp:1105:5:   instantiated from ‘typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, boost::function<R(T0)>&>::type boost::function<R(T0)>::operator=(Functor) [with Functor = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::detail::function_eval<0>, boost::fusion::vector<boost::phoenix::value<boost::phoenix::detail::function_ptr<0, void, void (*)()> >, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >, R = int, T0 = int, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, boost::function<R(T0)>&>::type = boost::function<int(int)>&]’
/opt/include/boost/signals2/detail/slot_template.hpp:156:9:   instantiated from ‘void boost::signals2::slot1<R, T1, SlotFunction>::init_slot_function(const F&) [with F = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::detail::function_eval<0>, boost::fusion::vector<boost::phoenix::value<boost::phoenix::detail::function_ptr<0, void, void (*)()> >, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >, R = int, T1 = int, SlotFunction = boost::function<int(int)>]’
/opt/include/boost/signals2/detail/slot_template.hpp:81:9:   instantiated from ‘boost::signals2::slot1<R, T1, SlotFunction>::slot1(const F&) [with F = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::detail::function_eval<0>, boost::fusion::vector<boost::phoenix::value<boost::phoenix::detail::function_ptr<0, void, void (*)()> >, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >, R = int, T1 = int, SlotFunction = boost::function<int(int)>]’
../../../examples/hello-world/hello-world-example.cpp:16:51:   instantiated from here
 /opt/include/boost/function/function_template.hpp:132:42: error: void value not ignored as it ought to be
 /opt/include/boost/function/function_template.hpp:133:9: error: control reaches end of non-void function [-Werror=return-type]


Many thanks,
Sak