Base type for adaptors. More...

#include <sigc++/adaptors/adaptor_trait.h>

Inheritance diagram for sigc::adapts< T_functor >:

List of all members.

Public Types
typedef adaptor_trait < T_functor >::result_type	result_type
typedef adaptor_trait < T_functor >::adaptor_type	adaptor_type

Public Member Functions
	adapts (const T_functor& _A_functor)
	Constructs an adaptor that wraps the passed functor.

Public Attributes
adaptor_type	functor_
	Adaptor that is invoked from operator()().

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Detailed Description

template<class T_functor>

struct sigc::adapts< T_functor >

Base type for adaptors.

adapts wraps adaptors, functors, function pointers and class methods. It contains a single member functor which is always a sigc::adaptor_base. The typedef adaptor_type defines the exact type that is used to store the adaptor, functor, function pointer or class method passed into the constructor. It differs from T_functor unless T_functor inherits from sigc::adaptor_base.

Example of a simple adaptor:

 template <class T_functor>
 struct my_adaptor : public sigc::adapts<T_functor>
 {
 template <class T_arg1=void, class T_arg2=void>
 struct deduce_result_type
 { typedef typename sigc::deduce_result_type<T_functor, T_arg1, T_arg2>::type type; };
 typedef typename sigc::functor_trait<T_functor>::result_type result_type;
 
 result_type
 operator()() const;
 
 template <class T_arg1>
 typename deduce_result_type<T_arg1>::type
 operator()(T_arg1 _A_arg1) const;
 
 template <class T_arg1, class T_arg2>
 typename deduce_result_type<T_arg1, T_arg2>::type
 operator()(T_arg1 _A_arg1, class T_arg2) const;
 
 // Constructs a my_adaptor object that wraps the passed functor.
 // Initializes adapts<T_functor>::functor_, which is invoked from operator()().
 explicit my_adaptor(const T_functor& _A_functor)
 : sigc::adapts<T_functor>(_A_functor) {}
 };
 
 template <class T_action, class T_functor>
 void visit_each(const T_action& _A_action,
 const my_adaptor<T_functor>& _A_target)
 {
 visit_each(_A_action, _A_target.functor_);
 }

If you implement your own adaptor, you must also provide your specialization of visit_each<>() that will forward the call to the functor(s) your adapter is wrapping. Otherwise, pointers stored within the functor won't be invalidated when a sigc::trackable object is destroyed and you can end up executing callbacks on destroyed objects.

Your adaptor and your specialization of visit_each<>() must be in the same namespace.

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Constructor & Destructor Documentation

template <class T_functor>

sigc::adapts< T_functor >::adapts ( const T_functor &  _A_functor )

inlineexplicit

Constructs an adaptor that wraps the passed functor.

Parameters:

_A_functor

Functor to invoke from operator()().