---
title: function
framework: driverkit
role: symbol
role_heading: Instance Property
path: driverkit/iouserclientmethoddispatch/function
---

# function

The function to call after validating all of the specified values.

## Declaration

```occ
IOUserClientMethodFunction function;
```

## Discussion

Discussion If this property is NULL and all checks pass, the system returns kIOReturnNoCompletion for the caller to implement the method.

## See Also

### Getting the Dispatch Properties

- [checkCompletionExists](driverkit/iouserclientmethoddispatch/checkcompletionexists.md)
- [checkScalarInputCount](driverkit/iouserclientmethoddispatch/checkscalarinputcount.md)
- [checkStructureInputSize](driverkit/iouserclientmethoddispatch/checkstructureinputsize.md)
- [checkScalarOutputCount](driverkit/iouserclientmethoddispatch/checkscalaroutputcount.md)
- [checkStructureOutputSize](driverkit/iouserclientmethoddispatch/checkstructureoutputsize.md)