hi::v1::callback< ResultType(ArgTypes...)> Class Template Reference

#include <hikogui/concurrency/callback.hpp>

Public Types
using	result_type = ResultType
using	weak_callback_type = weak_callback<ResultType(ArgTypes...)>

Public Member Functions
	callback (callback const &)=default
callback &	operator= (callback const &)=default
	callback (callback &&)=default
callback &	operator= (callback &&)=default
	callback (std::nullptr_t) noexcept
callback &	operator= (std::nullptr_t) noexcept
template<typename Func>
	callback (Func &&func)
void	reset () noexcept
long	use_count () const noexcept
	operator bool () const noexcept
template<typename... Args>
decltype(auto)	operator() (Args... args)
	Call the callback function.

Detailed Description

template<typename ResultType, typename... ArgTypes>
class hi::v1::callback< ResultType(ArgTypes...)>

A callback function.

This callback object holds a function object that can be called. It works mostly as std::function<R(Args...)>.

The ownership model of a callback is designed around a std::shared_ptr and std::weak_ptr.

In many cases the subscribe() function of an object will store a weak_callback and return a callback object. This caller of subscribe() will become the owner of the callback. When the callback is destroyed weak_callback can no longer be called and be automatically cleaned up.

This way subscribing a lambda-callback that captures the this pointer can be safely handled, by having the this object store the callback. When this gets destroyed, the callback is destroyed and the subscription is automatically cleaned up.

However it may still be dangerous when the callback is called from multiple threads.

The callback may also not re-enter from the same thread, nor is it allowed to destroy the callback from within the callback.

Template Parameters

R	The result of the function.
Args	The arguments of the function.

Member Function Documentation

operator()()

template<typename ResultType, typename... ArgTypes>

template<typename... Args>

decltype(auto) hi::v1::callback< ResultType(ArgTypes...)>::operator() ( Args... args )

inline

Call the callback function.

Note

A callback is not re-enterable from the same thread.

It is undefined behavior to destroy a callback while it is in-flight.

Parameters

args	The arguments forwarded to callback-function.

Returns

The result of the callback-function.

Exceptions

std::base_function_call	if the callback does not store a function object.
The	exception thrown from the callback-function.

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The documentation for this class was generated from the following file:

• hikogui/src/hikogui/concurrency/callback.hpp