libsigc++  2.99.2
Classes | Functions
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, class T_functor , class... T_bound>
decltype(auto) sigc::bind (const T_functor& _A_func, T_bound..._A_b)
 Creates an adaptor of type sigc::bind_functor which binds the passed argument to the passed functor. More...
 
template<class T_functor , class... T_type>
decltype(auto) sigc::bind (const T_functor& _A_func, T_type..._A_b)
 Creates an adaptor of type sigc::bind_functor which fixes the last arguments of the passed functor. More...
 
template<class T_return , class T_functor >
bind_return_functor< T_return, T_functor > sigc::bind_return (const T_functor& _A_functor, T_return _A_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.

Up to 7 arguments can be bound at a time. 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 sigc::bind() returns can be passed into sigc::signal::connect() directly.

Example:
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;
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;
void foo(bar&);
some_signal.connect(sigc::bind(&foo, std::ref(some_bar)));
// disconnected automatically if some_bar goes out of scope

Function Documentation

template <int I_location, class T_functor , class... T_bound>
decltype(auto) sigc::bind ( const T_functor &  _A_func,
T_bound...  _A_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
_A_funcFunctor that should be wrapped.
_A_b1Argument to bind to _A_func.
Returns
Adaptor that executes _A_func with the bound argument on invokation.
template <class T_functor , class... T_type>
decltype(auto) sigc::bind ( const T_functor &  _A_func,
T_type...  _A_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 _A_func.

Parameters
_A_funcFunctor that should be wrapped.
_A_bArguments to bind to _A_func.
Returns
Adaptor that executes _A_func with the bound argument on invokation.
template <class T_return , class T_functor >
bind_return_functor<T_return, T_functor> sigc::bind_return ( const T_functor &  _A_functor,
T_return  _A_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
_A_functorFunctor that should be wrapped.
_A_ret_valueArgument to fix the return value of _A_functor to.
Returns
Adaptor that executes _A_functor on invokation and returns _A_ret_value.