Shared Memory - Godot 4.4+

This is an addon for Godot 4.4+ that adds the SharedMemory class for creating, opening and directly accessing shared memory segments for inter-process communication (IPC).

Description

SharedMemory is an IPC mechanism that lets two or more processes access the same memory segment concurrently. A segment created by one process can be read and written by other processes. Any change becomes immediately visible to all processes that share the segment.

Note: SharedMemory does not provide synchronization methods or automatic cleanup. You must synchronize concurrent access to prevent race conditions.

How to use

Write (Godot → Python):

# Godot Shared Memory Example.
extends Node

const NAME : String = "SharedMemoryExample"
const SIZE : int = 1024

func _ready() -> void:
	var shm : SharedMemory = SharedMemory.new()
	if shm.create(NAME, SIZE, SharedMemory.LOCAL_SCOPE) == OK:
		shm.write(("Hello world from Godot Shared Memory!").to_utf8_buffer())

	await get_tree().create_timer(10).timeout

	shm.close()
	shm.unlink()

Read (Python):

# Python Shared Memory Example.
from multiprocessing import shared_memory
from multiprocessing import resource_tracker

NAME : str = "SharedMemoryExample"
SIZE : int = 1024

def main() -> None:
	shm : shared_memory.SharedMemory = shared_memory.SharedMemory(name=NAME, create=False, size=SIZE)

	resource_tracker.unregister(shm._name, 'shared_memory')

	data : bytes = bytes(shm.buf[:]).rstrip(b'\x00')

	print(data.decode("utf-8"))

	shm.close()

if __name__ == "__main__":
	main()

Hello world from Godot Shared Memory!

Write (Python → Godot):

# Python Shared Memory Example.
from multiprocessing import shared_memory
import time

NAME : str = "SharedMemoryExample"
SIZE : int = 1024

def main() -> None:
	shm : shared_memory.SharedMemory = shared_memory.SharedMemory(name=NAME, create=True, size=SIZE)

	data : bytes = b'Hello world from Python Shared Memory!'

	shm.buf[0:len(data)] = data

	time.sleep(10)

	shm.close()
	shm.unlink()

if __name__ == "__main__":
	main()

Read (Godot):

# Godot Shared Memory Example.
extends Node

const NAME : String = "SharedMemoryExample"
const SIZE : int = 1024

func rstrip(buffer : PackedByteArray) -> PackedByteArray:
	var out : PackedByteArray = buffer.duplicate()
	
	while out.size() > 0 and out[out.size() - 1] == 0:
		out.resize(out.size() - 1)
	
	return out

func _ready() -> void:
	var shm : SharedMemory = SharedMemory.new()
	
	if shm.open(NAME, SIZE) == OK:
		var data : PackedByteArray = shm.read()
		data = rstrip(data)
		print(data.get_string_from_utf8())
	
	shm.close()

Hello world from Python Shared Memory!

Links & Support

• Git-Hub

[ Support Email: interdreamsoft@gmail.com ]