---
title: offset
framework: corebluetooth
role: symbol
role_heading: Instance Property
path: corebluetooth/cbattrequest/offset
---

# offset

The zero-based index of the first byte for the read or write request.

## Declaration

```swift
var offset: Int { get }
```

## Discussion

Discussion You can use the value of this property to ensure that the ATT request is attempting to read or write within the proper bounds of the characteristic’s value. For an example of how to take a request’s offset property into account when responding to a read or write request, see Responding to Read and Write Requests from a Central.

## See Also

### Requesting to Read and Write Characteristic Values

- [central](corebluetooth/cbattrequest/central.md)
- [characteristic](corebluetooth/cbattrequest/characteristic.md)
- [value](corebluetooth/cbattrequest/value.md)