# AsRef<T>(void*)

> Gets a reference to a struct at a specific memory location.

## Definition

* **Type:** Method
* **Namespace:** [Unity.Collections.LowLevel.Unsafe](/engine/6000.3/script-reference/unity/collections/lowlevel/unsafe.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public static ref T AsRef<T>(void* ptr) where T : struct
```

### Parameters

**** (\[void\*]\(https\://learn.microsoft.com/dotnet/api/system.void)): A pointer to the memory location of the struct. Ensure the pointer is valid and correctly allocated.

### Returns

| Type | Description                                                                                                        |
| ---- | ------------------------------------------------------------------------------------------------------------------ |
| T    | A reference to the struct of type `T`. This reference allows changes to the struct at its current memory location. |

### Remarks

The `AsRef` method provides a reference to a struct directly in memory. This allows efficient data manipulation without copying. Use this method when performance is critical, and you must access data in-place. Improper use can lead to memory corruption, so always ensure pointer validity.

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

public class AsRefExample : MonoBehaviour
{
    struct Position
    {
        public float X;
        public float Y;
        public float Z;
    }

    void Start()
    {
        // Allocate memory for Position using stackalloc
        unsafe
        {
            Position* positionPtr = stackalloc Position[1];

            // Set initial values
            positionPtr->X = 1.0f;
            positionPtr->Y = 2.0f;
            positionPtr->Z = 3.0f;

            // Use AsRef to get a reference to the struct
            ref Position positionRef = ref UnsafeUtility.AsRef<Position>(positionPtr);

            // Modify the struct through the reference
            positionRef.X = 10.0f;
            positionRef.Y = 20.0f;
            positionRef.Z = 30.0f;

            // Output the modified values
            Debug.Log($"Modified Position: X = {positionPtr->X}, Y = {positionPtr->Y}, Z = {positionPtr->Z}");
        }
    }
}
```

Additional Resources: [UnsafeUtility.As](/engine/6000.3/script-reference/unity/collections/lowlevel/unsafe/unsafeutility/as.md).