.. index:: pair: class; EE::ObservableValue::WeakHandle
.. _doxid-class_e_e_1_1_observable_value_1_1_weak_handle:

class EE::ObservableValue::WeakHandle
=====================================

.. toctree::
	:hidden:

Overview
~~~~~~~~

Non-owning, lifetime-safe access used by adapters such as UIValueBinding. :ref:`More...<details-class_e_e_1_1_observable_value_1_1_weak_handle>`


.. ref-code-block:: cpp
	:class: doxyrest-overview-code-block

	#include <observablevalue.hpp>
	
	class WeakHandle {
	public:
		// methods
	
		bool :ref:`set<doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1a298f81e5cef082e7010988cef513bf29>`(const T& value) const;
		bool :ref:`set<doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1a7dc5f0ccf7c2ef03dda41a492b96b932>`(T&& value) const;
		std::optional<T> :ref:`get<doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1adf8d8da8e5d7b5a17766b34accc63224>`() const;
		:ref:`Connection<doxid-class_e_e_1_1_observable_value_1_1_connection>` :ref:`observe<doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1ae879757363bcc90756f4ef823781f129>`(:ref:`Callback<doxid-class_e_e_1_1_observable_value_1a53e49c3580bc69ffc87a473c9d638b9d>` callback) const;
		:target:`operator bool<doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1ab44fa5cc88dd07a8e7e91b039f76e9a7>`() const;
	};
.. _details-class_e_e_1_1_observable_value_1_1_weak_handle:

Detailed Documentation
~~~~~~~~~~~~~~~~~~~~~~

Non-owning, lifetime-safe access used by adapters such as UIValueBinding.

Operations fail harmlessly after the owning :ref:`ObservableValue <doxid-class_e_e_1_1_observable_value>` is destroyed. A :ref:`WeakHandle <doxid-class_e_e_1_1_observable_value_1_1_weak_handle>` does not make cross-thread access safe.

Methods
-------

.. index:: pair: function; set
.. _doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1a298f81e5cef082e7010988cef513bf29:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	bool set(const T& value) const



.. rubric:: Returns:

true when the owner still exists and accepted the set operation.

.. index:: pair: function; set
.. _doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1a7dc5f0ccf7c2ef03dda41a492b96b932:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	bool set(T&& value) const



.. rubric:: Returns:

true when the owner still exists and accepted the set operation.

.. index:: pair: function; get
.. _doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1adf8d8da8e5d7b5a17766b34accc63224:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	std::optional<T> get() const



.. rubric:: Returns:

A copy of the current value, or std::nullopt after the owner expires.

.. index:: pair: function; observe
.. _doxid-class_e_e_1_1_observable_value_1_1_weak_handle_1ae879757363bcc90756f4ef823781f129:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	:ref:`Connection<doxid-class_e_e_1_1_observable_value_1_1_connection>` observe(:ref:`Callback<doxid-class_e_e_1_1_observable_value_1a53e49c3580bc69ffc87a473c9d638b9d>` callback) const



.. rubric:: Returns:

A scoped observer connection, or an empty connection after owner expiration.