> For the complete documentation index, see [llms.txt](https://developer.magtek.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.magtek.com/sdks-and-tools/universal-sdk-documentation/ios/iconfigurationcallback-delegates.md). # IConfigurationCallback Delegates This interface invokes a callback function to receive data and/or a detailed response. To use, a class must implements the IConfigurationCallback Delegates interface. ### OnCalculateMAC This event is called when certain asynchronous IDeviceConfiguration operations need to have a MAC included with the request. {% code overflow="wrap" %} ``` (IResult*) OnCalculateMAC: (unsigned char) macType data: (NSData*) data; ``` {% endcode %}
ParameterDescription
macTypeType of Mac algorithm. For DynaFlex, use 0.
dataContains the data of the payload to MAC.
Return Value: Returns an IResult\* that contains the calculated MAC. ### OnProgress This event is called to update the host on the progress of an asynchronous IDeviceConfiguration operation. {% code overflow="wrap" %} ``` (void) OnProgress: (int) Progress; ``` {% endcode %}
ParameterDescription

progress

The progress of the configuration operation. Range:

0 - 100

Return Value: None ### OnResult This event is called to update the host when an asynchronous IDeviceConfiguration operation is completed. {% code overflow="wrap" %} ``` (void) OnResult: (MTU_StatusCode) status data: (NSData*) data; ``` {% endcode %}
ParameterDescription
statusAn enumerated MTU_StatusCode.
dataContains the data for the event.
Return Value: None **Example**: 
interface MTUSDK_DynaFlex : <IConfigurationCallback>
func OnCalculateMAC(_ macType: UInt8, data: Data) -> IResult
        {
                // Event handler
        }

func onProgress(_ progressValue: Int32)
        {
                // Event handler
        }
func onResult(_ status: MTU_StatusCode, data: Data)
        {
                // Event handler
        }

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