UnsafeUtility.ReleaseGCObject

Parameters

Description

Releases a GC handle obtained from UnsafeUtility.PinGCObjectAndGetAddress or UnsafeUtility.PinGCArrayAndGetDataAddress.

The ReleaseGCObject method unpins an object, allowing the garbage collector to manage its memory freely. Use this method to prevent resource leaks. Ensure you release each handle after finishing direct memory operations.

using Unity.Collections.LowLevel.Unsafe;
using UnityEngine;

public class ReleaseGCObjectExample : MonoBehaviour
{
    private struct MyStruct
    {
        public int value;
    }

    void Start()
    {
        // Box a struct
        object boxedStruct = new MyStruct { value = 10 };

        // Pin the object and get a GC handle
        unsafe
        {
            void* dataPtr = UnsafeUtility.PinGCObjectAndGetAddress(boxedStruct, out ulong gcHandle);

            // Access and modify data
            int objectHeaderSize = UnsafeUtility.SizeOf<long>() * 2;
            int* valuePtr = (int*)((byte*)dataPtr + objectHeaderSize);
            *valuePtr = 20;

            // Release the GC handle
            UnsafeUtility.ReleaseGCObject(gcHandle);
        }

        // Verify modification
        MyStruct modifiedStruct = (MyStruct)boxedStruct;
        Debug.Log($"Modified value: {modifiedStruct.value}"); // Outputs: 20

        // Confirm handle release
        Debug.Log("GC handle released.");
    }
}

Additional resources: UnsafeUtility.PinGCObjectAndGetAddress, UnsafeUtility.PinGCArrayAndGetDataAddress.