====== 42 Howto: Requests ======

===== Request and Wait for Reply =====

//How to add a "Request and Wait for Reply" to a Generic-Networking enabled DQMH module//

<WRAP left round tip 100%>
The Notifier helper VIs mentioned below can be found at: \\
''\Generic Networking Example_Source\Libraries\hse-libraries\hse-gennet\hse-gennet.lvlib''
</WRAP>

=== Steps needed ===

  - Add new DQMH Event "Request and Wait for Reply"
  - (in EHL) Add "DQMH-GenNet Add Notifier To Variant.vi" in newly created User Event: 
    - Copy "Wait Notifier" from "DQMH-GenNet Add Notifier To Variant.vi" to Clipboard and replace given "Wait Notifier" from "... Argument--cluster.ctl"
    - Wire cluster output to Event Data in and Wait Notifier input terminals of "DQMH-GenNet Add Notifier to Variant.vi"
    - Wire Variant Out terminal of "DQMH-GenNet Add Notifier to Variant.vi" to Message Data input of DQMH Enqueue Message
  - (in MHL) Add ''DQMH-GenNet Get Notifier from Variant.vi''
    - Replace Variant to Data.vi with “DQMH-GenNet get Notifier from Variant.vi”
    - Wire Wait Notifier output of "DQMH-GenNet Get Notifier from Variant.vi" to replace notifier input of Send Notification
    - Optional: Add ''Data To Variant'' for reply contents (otherwise it'll be implicit typecast)
  - Open the Request VI and fix:
    - Disconnect DQMH_WAIT_ARG cluster from DQMH_OBTAIN Obtain Notifier.vi
    - Wire a variant constant to element data type input of Obtain Notifier.vi
    - Add Variant to Data to notification output of DQMH_WAIT Wait on Notification.vi and wire DQMH_WAIT_ARG cluster as data type
    - See image below or use "Do something with answer" as template

//The screenshots show reworking a ''Get FIFO Contents'' request//

{{ :kb:labview-frameworks:dqmh:dqmh-gennet-ehl.png?nolink |}}

{{ :kb:labview-frameworks:dqmh:dqmh-gennet-mhl.png?nolink |}}

{{ :kb:labview-frameworks:dqmh:dqmh-gennet-req.png?nolink |}}