godot-docs/classes/class_semaphore.rst

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.. _class_Semaphore:

Semaphore
=========

**Inherits:** :ref:`Reference<class_Reference>` **<** :ref:`Object<class_Object>`

**Category:** Core

Brief Description
-----------------

A synchronization Semaphore.

Methods
-------

+---------------------------------------+------------------------------------------------------+
| :ref:`Error<enum_@GlobalScope_Error>` | :ref:`post<class_Semaphore_method_post>` **(** **)** |
+---------------------------------------+------------------------------------------------------+
| :ref:`Error<enum_@GlobalScope_Error>` | :ref:`wait<class_Semaphore_method_wait>` **(** **)** |
+---------------------------------------+------------------------------------------------------+

Description
-----------

A synchronization Semaphore. Element used to synchronize multiple :ref:`Thread<class_Thread>`\ s. Initialized to zero on creation. Be careful to avoid deadlocks. For a binary version, see :ref:`Mutex<class_Mutex>`.

Method Descriptions
-------------------

.. _class_Semaphore_method_post:

- :ref:`Error<enum_@GlobalScope_Error>` **post** **(** **)**

Lowers the ``Semaphore``, allowing one more thread in. Returns :ref:`@GlobalScope.OK<class_@GlobalScope_constant_OK>` on success, :ref:`@GlobalScope.ERR_BUSY<class_@GlobalScope_constant_ERR_BUSY>` otherwise.

----

.. _class_Semaphore_method_wait:

- :ref:`Error<enum_@GlobalScope_Error>` **wait** **(** **)**

Tries to wait for the ``Semaphore``, if its value is zero, blocks until non-zero. Returns :ref:`@GlobalScope.OK<class_@GlobalScope_constant_OK>` on success, :ref:`@GlobalScope.ERR_BUSY<class_@GlobalScope_constant_ERR_BUSY>` otherwise.