103 lines
3.9 KiB
ReStructuredText
103 lines
3.9 KiB
ReStructuredText
:github_url: hide
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.. DO NOT EDIT THIS FILE!!!
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.. Generated automatically from Godot engine sources.
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.. Generator: https://github.com/godotengine/godot/tree/3.6/doc/tools/make_rst.py.
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.. XML source: https://github.com/godotengine/godot/tree/3.6/doc/classes/Semaphore.xml.
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.. _class_Semaphore:
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Semaphore
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=========
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**Inherits:** :ref:`Reference<class_Reference>` **<** :ref:`Object<class_Object>`
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A synchronization semaphore.
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.. rst-class:: classref-introduction-group
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Description
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-----------
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A synchronization semaphore which can be 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>`.
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\ **Warning:**\
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To guarantee that the operating system is able to perform proper cleanup (no crashes, no deadlocks), these conditions must be met:
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- By the time a **Semaphore**'s reference count reaches zero and therefore it is destroyed, no threads must be waiting on it.
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- By the time a :ref:`Thread<class_Thread>`'s reference count reaches zero and therefore it is destroyed, it must not be waiting on any semaphore.
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.. rst-class:: classref-introduction-group
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Tutorials
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---------
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- :doc:`../tutorials/performance/threads/using_multiple_threads`
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.. rst-class:: classref-reftable-group
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Methods
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-------
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.. table::
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:widths: auto
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+---------------------------------------+--------------------------------------------------------------+
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| :ref:`Error<enum_@GlobalScope_Error>` | :ref:`post<class_Semaphore_method_post>` **(** **)** |
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+---------------------------------------+--------------------------------------------------------------+
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| :ref:`Error<enum_@GlobalScope_Error>` | :ref:`try_wait<class_Semaphore_method_try_wait>` **(** **)** |
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+---------------------------------------+--------------------------------------------------------------+
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| :ref:`Error<enum_@GlobalScope_Error>` | :ref:`wait<class_Semaphore_method_wait>` **(** **)** |
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+---------------------------------------+--------------------------------------------------------------+
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.. rst-class:: classref-section-separator
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----
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.. rst-class:: classref-descriptions-group
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Method Descriptions
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-------------------
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.. _class_Semaphore_method_post:
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.. rst-class:: classref-method
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:ref:`Error<enum_@GlobalScope_Error>` **post** **(** **)**
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Lowers the **Semaphore**, allowing one more thread in.
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\ **Note:** This method internals' can't possibly fail, but an error code is returned for backwards compatibility, which will always be :ref:`@GlobalScope.OK<class_@GlobalScope_constant_OK>`.
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.. rst-class:: classref-item-separator
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----
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.. _class_Semaphore_method_try_wait:
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.. rst-class:: classref-method
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:ref:`Error<enum_@GlobalScope_Error>` **try_wait** **(** **)**
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Like :ref:`wait<class_Semaphore_method_wait>`, but won't block, so if the value is zero, fails immediately and returns :ref:`@GlobalScope.ERR_BUSY<class_@GlobalScope_constant_ERR_BUSY>`. If non-zero, it returns :ref:`@GlobalScope.OK<class_@GlobalScope_constant_OK>` to report success.
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.. rst-class:: classref-item-separator
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----
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.. _class_Semaphore_method_wait:
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.. rst-class:: classref-method
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:ref:`Error<enum_@GlobalScope_Error>` **wait** **(** **)**
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Waits for the **Semaphore**, if its value is zero, blocks until non-zero.
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\ **Note:** This method internals' can't possibly fail, but an error code is returned for backwards compatibility, which will always be :ref:`@GlobalScope.OK<class_@GlobalScope_constant_OK>`.
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.. |virtual| replace:: :abbr:`virtual (This method should typically be overridden by the user to have any effect.)`
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.. |const| replace:: :abbr:`const (This method has no side effects. It doesn't modify any of the instance's member variables.)`
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.. |vararg| replace:: :abbr:`vararg (This method accepts any number of arguments after the ones described here.)`
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.. |static| replace:: :abbr:`static (This method doesn't need an instance to be called, so it can be called directly using the class name.)`
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