a quick question regarding boost::bind, with a test case
Hello all: I have a quick question regarding boost::bind, as the subject line says. This isn't a very viable example, but it works well enough to show what I want. I have a callback I am using boost::bind to bind to, and I am passing a function object in as shown by the following code: #include <cstdio> #include <boost/bind.hpp> #include <boost/function.hpp> class Math { public: void Add(int a, int b, int c, boost::function<void (int)> printer); { printer(a+b+c); } }; void Printer(int p) { printf("%d\n", p); }How might I make this work? I am not sure how I can pass that as the fourth argument so that the function can be called like (1,2,3) etc. Also, in the actual problem I moved the function object to the first argument, (which just ment changing the prototype and actual function), but I still got errors. -- Thanks, Ty
AMDG On 04/11/2011 10:44 AM, Littlefield, Tyler wrote:
I have a quick question regarding boost::bind, as the subject line says.
This isn't a very viable example, but it works well enough to show what I want. I have a callback I am using boost::bind to bind to, and I am passing a function object in as shown by the following code: #include <cstdio> #include <boost/bind.hpp> #include <boost/function.hpp>
class Math { public: void Add(int a, int b, int c, boost::function<void (int)> printer); { printer(a+b+c); } };
void Printer(int p) { printf("%d\n", p); }How might I make this work? I am not sure how I can pass that as the fourth argument so that the function can be called like (1,2,3) etc. Also, in the actual problem I moved the function object to the first argument, (which just ment changing the prototype and actual function), but I still got errors.
I'm not sure exactly what you're trying to do, but the following should work: boost::bind(&Math::Add, Math(), _1, _2, _3, &Printer)(1, 2, 3) In Christ, Steven Watanabe
Hello: Here is what I'm going for; maybe this will explain I have the following code in my project: AddOlc("name", "Please enter the name of the object", STRING, boost::bind(OlcString, _1, _2, _3, boost::bind(&Entity::GetName, this), boost::bind(&Entity::SetName, this, _1))); OlcString: void OlcString(Entity* ed, Player* mob, const Variant* input, boost::function<std::string ()> get, boost::function<void (const std::string&)> set) { if (input->Typeof() != VAR_STR) { mob->Message(MSG_ERROR, "Invalid input."); return; } set(input->GetStr()); } The point is for the callback (OlcString) to use the setter to set the name of the object, which is not what is happening. Here are the compile erorrs: 12:19:26: Compiling entity.cpp. In file included from /usr/local/include/boost/bind.hpp:22:0, from entity.cpp:5: /usr/local/include/boost/bind/bind.hpp: In member function ‘void boost::_bi::list5<A1, A2, A3, A4, A5>::operator()(boost::_bi::type<void>, F&, A&, int) [with F = void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), A = boost::_bi::list3<Entity*&, Player*&, const Variant*&>, A1 = boost::arg<1>, A2 = boost::arg<2>, A3 = boost::arg<3>, A4 = boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, A5 = boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > >]’: /usr/local/include/boost/bind/bind_template.hpp:116:59: instantiated from ‘boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()(A1&, A2&, A3&) [with A1 = Entity*, A2 = Player*, A3 = const Variant*, R = void, F = void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), L = boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > >, boost::_bi::bind_t<R, F, L>::result_type = void]’ /usr/local/include/boost/function/function_template.hpp:153:11: instantiated from ‘static void boost::detail::function::void_function_obj_invoker3<FunctionObj, R, T0, T1, T2>::invoke(boost::detail::function::function_buffer&, T0, T1, T2) [with FunctionObj = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*]’ /usr/local/include/boost/function/function_template.hpp:907:60: instantiated from ‘void boost::function3<R, T1, T2, T3>::assign_to(Functor) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*]’ /usr/local/include/boost/function/function_template.hpp:722:7: instantiated from ‘boost::function3<R, T1, T2, T3>::function3(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’ /usr/local/include/boost/function/function_template.hpp:1042:16: instantiated from ‘boost::function<R(T0, T1, T2)>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’ entity.cpp:27:177: instantiated from here /usr/local/include/boost/bind/bind.hpp:525:9: error: conversion from ‘boost::_bi::result_traits<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char, std::char_traits<char>, std::allocator<char> >&>
::type’ to non-scalar type ‘boost::function<void(const std::basic_string<char>&)>’ requested /usr/local/include/boost/bind/bind.hpp: In member function ‘void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F&, A&, int) [with F = boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, A = const boost::_bi::list3<Entity*&, Player*&, const Variant*&>, A1 = boost::_bi::value<Entity*>, A2 = boost::arg<1>]’: /usr/local/include/boost/bind/bind_template.hpp:318:59: instantiated from ‘boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::eval(A&) [with A = const boost::_bi::list3<Entity*&, Player*&, const Variant*&>, R = void, F = boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, L = boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> >, boost::_bi::bind_t<R, F, L>::result_type = void]’ /usr/local/include/boost/bind/bind.hpp:376:136: instantiated from ‘typename boost::_bi::result_traits<R, F>::type boost::_bi::list3<A1, A2, A3>::operator[](boost::_bi::bind_t<R, F, L>&) const [with R = void, F = boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, L = boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> >, A1 = Entity*&, A2 = Player*&, A3 = const Variant*&, typename boost::_bi::result_traits<R, F>::type = void]’ /usr/local/include/boost/bind/bind.hpp:525:9: instantiated from ‘void boost::_bi::list5<A1, A2, A3, A4, A5>::operator()(boost::_bi::type<void>, F&, A&, int) [with F = void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), A = boost::_bi::list3<Entity*&, Player*&, const Variant*&>, A1 = boost::arg<1>, A2 = boost::arg<2>, A3 = boost::arg<3>, A4 = boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, A5 = boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > >]’ /usr/local/include/boost/bind/bind_template.hpp:116:59: instantiated from ‘boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()(A1&, A2&, A3&) [with A1 = Entity*, A2 = Player*, A3 = const Variant*, R = void, F = void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), L = boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > >, boost::_bi::bind_t<R, F, L>::result_type = void]’ /usr/local/include/boost/function/function_template.hpp:153:11: instantiated from ‘static void boost::detail::function::void_function_obj_invoker3<FunctionObj, R, T0, T1, T2>::invoke(boost::detail::function::function_buffer&, T0, T1, T2) [with FunctionObj = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*]’ /usr/local/include/boost/function/function_template.hpp:907:60: instantiated from ‘void boost::function3<R, T1, T2, T3>::assign_to(Functor) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*]’ /usr/local/include/boost/function/function_template.hpp:722:7: instantiated from ‘boost::function3<R, T1, T2, T3>::function3(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’ /usr/local/include/boost/function/function_template.hpp:1042:16: instantiated from ‘boost::function<R(T0, T1, T2)>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’ entity.cpp:27:177: instantiated from here /usr/local/include/boost/bind/bind.hpp:313:9: error: no match for call to ‘(boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>) (Entity*&, Entity*&)’ /usr/local/include/boost/bind/mem_fn_template.hpp:163:7: note: candidates are: R boost::_mfi::mf1<R, T, A1>::operator()(T*, A1) const [with R = void, T = Entity, A1 = const std::basic_string<char>&] /usr/local/include/boost/bind/mem_fn_template.hpp:184:7: note: R boost::_mfi::mf1<R, T, A1>::operator()(T&, A1) const [with R = void, T = Entity, A1 = const std::basic_string<char>&] In file included from /usr/local/include/boost/function/detail/maybe_include.hpp:13:0, from /usr/local/include/boost/function/detail/function_iterate.hpp:14, from /usr/local/include/boost/preprocessor/iteration/detail/iter/forward1.hpp:47, from /usr/local/include/boost/function.hpp:64, from mud.h:4, from entity.h:10, from entity.cpp:6: /usr/local/include/boost/function/function_template.hpp: In static member function ‘static R boost::detail::function::function_obj_invoker0<FunctionObj, R>::invoke(boost::detail::function::function_buffer&) [with FunctionObj = std::basic_string<char>, R = std::basic_string<char>]’: /usr/local/include/boost/function/function_template.hpp:907:60: instantiated from ‘void boost::function0<R>::assign_to(Functor) [with Functor = std::basic_string<char>, R = std::basic_string<char>]’ /usr/local/include/boost/function/function_template.hpp:722:7: instantiated from ‘boost::function0<R>::function0(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = std::basic_string<char>, R = std::basic_string<char>, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’ /usr/local/include/boost/function/function_template.hpp:1042:16: instantiated from ‘boost::function<R()>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = std::basic_string<char>, R = std::basic_string<char>, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’ /usr/local/include/boost/bind/bind.hpp:525:9: instantiated from ‘void boost::_bi::list5<A1, A2, A3, A4, A5>::operator()(boost::_bi::type<void>, F&, A&, int) [with F = void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), A = boost::_bi::list3<Entity*&, Player*&, const Variant*&>, A1 = boost::arg<1>, A2 = boost::arg<2>, A3 = boost::arg<3>, A4 = boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, A5 = boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > >]’ /usr/local/include/boost/bind/bind_template.hpp:116:59: instantiated from ‘boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()(A1&, A2&, A3&) [with A1 = Entity*, A2 = Player*, A3 = const Variant*, R = void, F = void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), L = boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > >, boost::_bi::bind_t<R, F, L>::result_type = void]’ /usr/local/include/boost/function/function_template.hpp:153:11: instantiated from ‘static void boost::detail::function::void_function_obj_invoker3<FunctionObj, R, T0, T1, T2>::invoke(boost::detail::function::function_buffer&, T0, T1, T2) [with FunctionObj = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*]’ /usr/local/include/boost/function/function_template.hpp:907:60: instantiated from ‘void boost::function3<R, T1, T2, T3>::assign_to(Functor) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*]’ /usr/local/include/boost/function/function_template.hpp:722:7: instantiated from ‘boost::function3<R, T1, T2, T3>::function3(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’ /usr/local/include/boost/function/function_template.hpp:1042:16: instantiated from ‘boost::function<R(T0, T1, T2)>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::_bi::bind_t<void, void (*)(Entity*, Player*, const Variant*, boost::function<std::basic_string<char>()>, boost::function<void(const std::basic_string<char>&)>), boost::_bi::list5<boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::_bi::bind_t<std::basic_string<char>, boost::_mfi::cmf0<std::basic_string<char>, Entity>, boost::_bi::list1<boost::_bi::value<Entity*> > >, boost::_bi::bind_t<void, boost::_mfi::mf1<void, Entity, const std::basic_string<char>&>, boost::_bi::list2<boost::_bi::value<Entity*>, boost::arg<1> > > > >, R = void, T0 = Entity*, T1 = Player*, T2 = const Variant*, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’ entity.cpp:27:177: instantiated from here /usr/local/include/boost/function/function_template.hpp:132:42: error: no match for call to ‘(std::basic_string<char>) ()’ make: *** [entity.o] Error 1
Thanks in advance, Ty On 4/11/2011 12:12 PM, Steven Watanabe wrote:
AMDG
On 04/11/2011 10:44 AM, Littlefield, Tyler wrote:
I have a quick question regarding boost::bind, as the subject line says.
This isn't a very viable example, but it works well enough to show what I want. I have a callback I am using boost::bind to bind to, and I am passing a function object in as shown by the following code: #include <cstdio> #include <boost/bind.hpp> #include <boost/function.hpp>
class Math { public: void Add(int a, int b, int c, boost::function<void (int)> printer); { printer(a+b+c); } };
void Printer(int p) { printf("%d\n", p); }How might I make this work? I am not sure how I can pass that as the fourth argument so that the function can be called like (1,2,3) etc. Also, in the actual problem I moved the function object to the first argument, (which just ment changing the prototype and actual function), but I still got errors.
I'm not sure exactly what you're trying to do, but the following should work: boost::bind(&Math::Add, Math(), _1, _2, _3, &Printer)(1, 2, 3)
In Christ, Steven Watanabe _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
-- Thanks, Ty
AMDG On 04/11/2011 11:19 AM, Littlefield, Tyler wrote:
Hello: Here is what I'm going for; maybe this will explain I have the following code in my project: AddOlc("name", "Please enter the name of the object", STRING, boost::bind(OlcString, _1, _2, _3, boost::bind(&Entity::GetName, this), boost::bind(&Entity::SetName, this, _1))); OlcString: void OlcString(Entity* ed, Player* mob, const Variant* input, boost::function<std::string ()> get, boost::function<void (const std::string&)> set) { if (input->Typeof() != VAR_STR) { mob->Message(MSG_ERROR, "Invalid input."); return; }
set(input->GetStr()); }
Oh. If you're using nested binds like this, you need to use protect. In Christ, Steven Watanabe
On Mon, Apr 11, 2011 at 6:44 PM, Littlefield, Tyler <tyler@tysdomain.com> wrote:
Hello all: I have a quick question regarding boost::bind, as the subject line says.
This isn't a very viable example, but it works well enough to show what I want. I have a callback I am using boost::bind to bind to, and I am passing a function object in as shown by the following code: #include <cstdio> #include <boost/bind.hpp> #include <boost/function.hpp>
class Math { public: void Add(int a, int b, int c, boost::function<void (int)> printer); { printer(a+b+c); } };
void Printer(int p) { printf("%d\n", p); }How might I make this work? I am not sure how I can pass that as the fourth argument so that the function can be called like (1,2,3) etc. Also, in the actual problem I moved the function object to the first argument, (which just ment changing the prototype and actual function), but I still got errors.
Your test case seems to be missing the thing that is causing you problems, and the bits provided don't compile. The following program works for me: #include <cstdio> #include <boost/bind.hpp> #include <boost/function.hpp> class Math { public: void Add(int a, int b, int c, boost::function<void (int)> printer) { printer(a+b+c); } }; void Printer(int p) { printf("%d\n", p); } int main() { Math m; m.Add(5,6,7,boost::bind(&Printer,_1)); } Regards, Pete
participants (3)
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Littlefield, Tyler -
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Steven Watanabe