---
title: completion
framework: driverkit
role: symbol
role_heading: Instance Property
path: driverkit/iouserclientmethodarguments/completion
---

# completion

An action for processing asynchronous data received from the service.

## Declaration

```occ
OSAction * completion;
```

## Discussion

Discussion The system retains this method only during the invocation of ExternalMethod. Retain this method yourself if you intend to use it outside of that invocation.

## See Also

### Getting the Method Arguments

- [version](driverkit/iouserclientmethodarguments/version.md)
- [selector](driverkit/iouserclientmethodarguments/selector.md)
- [scalarInput](driverkit/iouserclientmethodarguments/scalarinput.md)
- [scalarInputCount](driverkit/iouserclientmethodarguments/scalarinputcount.md)
- [structureInput](driverkit/iouserclientmethodarguments/structureinput.md)
- [structureInputDescriptor](driverkit/iouserclientmethodarguments/structureinputdescriptor.md)
- [scalarOutput](driverkit/iouserclientmethodarguments/scalaroutput.md)
- [scalarOutputCount](driverkit/iouserclientmethodarguments/scalaroutputcount.md)
- [structureOutput](driverkit/iouserclientmethodarguments/structureoutput.md)
- [structureOutputDescriptor](driverkit/iouserclientmethodarguments/structureoutputdescriptor.md)
- [structureOutputMaximumSize](driverkit/iouserclientmethodarguments/structureoutputmaximumsize.md)