godot/doc/classes/Semaphore.xml
Rémi Verschelde 81064cc239
Doctool: Remove version attribute from XML header
We don't use that info for anything, and it generates unnecessary diffs
every time we bump the minor version (and CI failures if we forget to
sync some files from opt-in modules (mono, text_server_fb).
2023-07-06 10:08:21 +02:00

37 lines
1.8 KiB
XML

<?xml version="1.0" encoding="UTF-8" ?>
<class name="Semaphore" inherits="RefCounted" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
<brief_description>
A synchronization mechanism used to control access to a shared resource by [Thread]s.
</brief_description>
<description>
A synchronization semaphore that can be used to synchronize multiple [Thread]s. Initialized to zero on creation. For a binary version, see [Mutex].
[b]Warning:[/b] Semaphores must be used carefully to avoid deadlocks.
[b]Warning:[/b] To guarantee that the operating system is able to perform proper cleanup (no crashes, no deadlocks), these conditions must be met:
- When a [Semaphore]'s reference count reaches zero and it is therefore destroyed, no threads must be waiting on it.
- When a [Thread]'s reference count reaches zero and it is therefore destroyed, it must not be waiting on any semaphore.
</description>
<tutorials>
<link title="Using multiple threads">$DOCS_URL/tutorials/performance/using_multiple_threads.html</link>
<link title="Thread-safe APIs">$DOCS_URL/tutorials/performance/thread_safe_apis.html</link>
</tutorials>
<methods>
<method name="post">
<return type="void" />
<description>
Lowers the [Semaphore], allowing one more thread in.
</description>
</method>
<method name="try_wait">
<return type="bool" />
<description>
Like [method wait], but won't block, so if the value is zero, fails immediately and returns [code]false[/code]. If non-zero, it returns [code]true[/code] to report success.
</description>
</method>
<method name="wait">
<return type="void" />
<description>
Waits for the [Semaphore], if its value is zero, blocks until non-zero.
</description>
</method>
</methods>
</class>