.. _doc_what_is_gdextension:

What is GDExtension?
====================

Introduction
------------

**GDExtension** is a Godot-specific technology that lets the engine interact with
native `shared libraries <https://en.wikipedia.org/wiki/Library_(computing)#Shared_libraries>`__
at run-time. You can use it to run native code without compiling it with the engine.

.. note:: GDExtension is *not* a scripting language and has no relation to
          :ref:`GDScript <doc_gdscript>`.

Differences between GDExtension and C++ modules
-----------------------------------------------

You can use both GDExtension and :ref:`C++ modules <doc_custom_modules_in_cpp>` to
run C or C++ code in a Godot project.

They also both allow you to integrate third-party libraries into Godot. The one
you should choose depends on your needs.

.. warning::

    Our long-term goal is that GDExtensions targeting an earlier version of
    Godot will work in later minor versions, but not vice-versa. For example, a
    GDExtension targeting Godot 4.2 should work just fine in Godot 4.3, but one
    targeting Godot 4.3 won't work in Godot 4.2.

    However, GDExtension is currently *experimental*, which means that we may
    break compatibility in order to fix major bugs or include critical features.
    For example, GDExtensions created for Godot 4.0 aren't compatible with Godot
    4.1 (see :ref:`updating_your_gdextension_for_godot_4_1`).

Advantages of GDExtension
^^^^^^^^^^^^^^^^^^^^^^^^^

Unlike modules, GDExtension doesn't require compiling the engine's source code,
making it easier to distribute your work. It gives you access to most of the API
available to GDScript and C#, allowing you to code game logic with full control
regarding performance. It's ideal if you need high-performance code you'd like
to distribute as an add-on in the :ref:`asset library <doc_what_is_assetlib>`.

Also:

- GDExtension is not limited to C and C++. Thanks to :ref:`third-party bindings
  <doc_what_is_gdnative_third_party_bindings>`, you can use it with many other
  languages.
- You can use the same compiled GDExtension library in the editor and exported
  project. With C++ modules, you have to recompile all the export templates you
  plan to use if you require its functionality at run-time.
- GDExtension only requires you to compile your library, not the whole engine.
  That's unlike C++ modules, which are statically compiled into the engine.
  Every time you change a module, you need to recompile the engine. Even with
  incremental builds, this process is slower than using GDExtension.

Advantages of C++ modules
^^^^^^^^^^^^^^^^^^^^^^^^^

We recommend :ref:`C++ modules <doc_custom_modules_in_cpp>` in cases where
GDExtension isn't enough:

- C++ modules provide deeper integration into the engine. GDExtension's access
  is not as deep as static modules.
- You can use C++ modules to provide additional features in a project without
  carrying native library files around. This extends to exported projects.

.. note::

    If you notice that specific systems are not accessible via GDExtension
    but are via custom modules, feel free to open an issue on the
    `godot-cpp repository <https://github.com/godotengine/godot-cpp>`__
    to discuss implementation options for exposing the missing functionality.

Supported languages
-------------------

The Godot developers officially support the following language bindings for
GDExtension:

- C++ :ref:`(tutorial) <doc_gdextension_cpp_example>`

.. note::

    There are no plans to support additional languages with GDExtension officially.
    That said, the community offers several bindings for other languages (see
    below).

.. _doc_what_is_gdnative_third_party_bindings:

The bindings below are developed and maintained by the community:

.. Binding developers: Feel free to open a pull request to add your binding if it's well-developed enough to be used in a project.
.. Please keep languages sorted in alphabetical order.

- `D <https://github.com/godot-dlang/godot-dlang>`__
- `Go <https://github.com/grow-graphics/gd>`__
- `Haxe <https://hxgodot.github.io/>`__
- `Rust <https://github.com/godot-rust/gdext>`__
- `Swift <https://github.com/migueldeicaza/SwiftGodot>`__

.. note::

    Not all bindings mentioned here may be production-ready. Make sure to
    research options thoroughly before starting a project with one of those.
    Also, double-check whether the binding is compatible with the Godot version
    you're using.

Version compatibility
---------------------

GDExtension add-ons compiled for a given Godot version are only guaranteed to work
with the same minor release series. For example, a GDExtension add-on compiled for
Godot 4.0 will only work with Godot 4.0, 4.0.1, 4.0.2. In addition, GDExtension is
not compatible with Godot 3.x.

GDExtension add-ons are also only compatible with engine builds that use the
level of floating-point precision the extension was compiled for. This means
that if you use a engine build with double-precision floats, the extension must
also be compiled for double-precision floats. See
:ref:`doc_large_world_coordinates` for details.