bind(), bind_return()

sigc::bind() alters an arbitrary functor by fixing arguments to certain values. More...

Classes
struct	sigc::bind_functor< I_location, T_functor, T_bound >
	Adaptor that binds arguments to the wrapped functor. More...
struct	sigc::bind_functor<-1, T_functor, T_type... >
	Adaptor that binds argument(s) to the wrapped functor. More...
struct	sigc::bind_return_functor< T_return, T_functor >
	Adaptor that fixes the return value of the wrapped functor. More...

Functions
template<int I_location, typename T_functor , typename... T_bound>
decltype(auto)	sigc::bind (const T_functor & func, T_bound... b)
	Creates an adaptor of type sigc::bind_functor which binds the passed argument to the passed functor. More...
template<typename T_functor , typename... T_type>
decltype(auto)	sigc::bind (const T_functor & func, T_type... b)
	Creates an adaptor of type sigc::bind_functor which fixes the last arguments of the passed functor. More...
template<typename T_return , typename T_functor >
bind_return_functor< T_return, T_functor >	sigc::bind_return (const T_functor & functor, T_return ret_value)
	Creates an adaptor of type sigc::bind_return_functor which fixes the return value of the passed functor to the passed argument. More...

Detailed Description

sigc::bind() alters an arbitrary functor by fixing arguments to certain values.

For single argument binding, overloads of sigc::bind() are provided that let you specify the zero-based position of the argument to fix with the first template parameter. (A value of -1 fixes the last argument so sigc::bind<-1>() gives the same result as sigc::bind().) The types of the arguments can optionally be specified if not deduced.

Examples:

void foo(int, int, int);
// single argument binding ...
sigc::bind(&foo,1)(2,3);     //fixes the last (third) argument and calls foo(2,3,1)
sigc::bind<-1>(&foo,1)(2,3); //same as bind(&foo,1)(2,3) (calls foo(2,3,1))
sigc::bind<0>(&foo,1)(2,3);  //fixes the first argument and calls foo(1,2,3)
sigc::bind<1>(&foo,1)(2,3);  //fixes the second argument and calls foo(2,1,3)
sigc::bind<2>(&foo,1)(2,3);  //fixes the third argument and calls foo(2,3,1)
// multi argument binding ...
sigc::bind(&foo,1,2)(3);     //fixes the last two arguments and calls foo(3,1,2)
sigc::bind(&foo,1,2,3)();    //fixes all three arguments and calls foo(1,2,3)

The functor that sigc::bind() returns can be passed directly into sigc::signal::connect() or sigc::signal::connect_first().

Example:

sigc::signal<void()> some_signal;
void foo(int);
some_signal.connect(sigc::bind(&foo,1));

sigc::bind_return() alters an arbitrary functor by fixing its return value to a certain value.

Example:

void foo();
std::cout << sigc::bind_return(&foo, 5)(); // calls foo() and returns 5

You can bind references to functors by passing the objects through the std::ref() helper function.

Example:

int some_int;
sigc::signal<void()> some_signal;
void foo(int&);
some_signal.connect(sigc::bind(&foo, std::ref(some_int)));

If you bind an object of a sigc::trackable derived type to a functor by reference, a slot assigned to the bind adaptor is cleared automatically when the object goes out of scope.

Example:

struct bar : public sigc::trackable {} some_bar;
sigc::signal<void()> some_signal;
void foo(bar&);
some_signal.connect(sigc::bind(&foo, std::ref(some_bar)));
  // disconnected automatically if some_bar goes out of scope

Function Documentation

bind() [1/2]

template <int I_location, typename T_functor , typename... T_bound>

decltype(auto) sigc::bind ( const T_functor &  func, T_bound...  b  )

inline

Creates an adaptor of type sigc::bind_functor which binds the passed argument to the passed functor.

The optional template argument I_location specifies the zero-based position of the argument to be fixed (-1 stands for the last argument).

Parameters

func	Functor that should be wrapped.
b	Arguments to bind to func.

Returns

Adaptor that executes func with the bound argument on invocation.

bind() [2/2]

template <typename T_functor , typename... T_type>

decltype(auto) sigc::bind ( const T_functor &  func, T_type...  b  )

inline

Creates an adaptor of type sigc::bind_functor which fixes the last arguments of the passed functor.

This function overload fixes the last arguments of func.

Parameters

func	Functor that should be wrapped.
b	Arguments to bind to func.

Returns

Adaptor that executes func with the bound argument on invocation.

bind_return()

template <typename T_return , typename T_functor >

bind_return_functor<T_return, T_functor> sigc::bind_return ( const T_functor &  functor, T_return  ret_value  )

inline

Creates an adaptor of type sigc::bind_return_functor which fixes the return value of the passed functor to the passed argument.

Parameters

functor	Functor that should be wrapped.
ret_value	Argument to fix the return value of functor to.

Returns

Adaptor that executes functor on invocation and returns ret_value.