VFN_OverrideLineItem()

       // Example Program: T_OVRLNITM
       // Description:
       //   This is a test program to illustrate how to use the
       //   VFN_OverrideLineItem() subprocedure to change the values for an
       //   existing MERCHANDISE line item.
       //
       //   This program assumes you have already called VFN_StartSession() to
       //   open a session with your device, and that you will call
       //   VFN_EndSession() afterwards.

       Ctl-Opt DftActGrp(*No) ActGrp(*Caller) BndDir('PTTIBND');

       /COPY QRPGLECPY,VFNCB

       // This is included for demo output purposes.
       Dcl-Pr WriteToJobLog Int(10) Extproc('Qp0zLprintf');
         pString Pointer Value Options(*String);
       End-Pr;
       Dcl-C NewLine x'15';

       // This will capture returned error information
       Dcl-Ds ErrorDS LikeDS(VFN_ErrorDS_t) Inz(*LikeDS);
       // This will be used to pass request information to the API call
       Dcl-Ds OverrideLineItemReqDS LikeDS(VFN_OverrideLineItemReqDS_t)
                                    Inz(*LikeDS);
       // This will store parsed response data from the API call
       Dcl-Ds OverrideLineItemRspDS LikeDS(VFN_OverrideLineItemRspDS_t)
                                    Inz(*LikeDS);

       reset ErrorDS;
       reset OverrideLineItemReqDS;
       reset OverrideLineItemRspDS;

       // This must be a device that has been successfully registered with
       //  VFN_Register() and which exists in VFNDVC.
       OverrideLineItemReqDS.DeviceID = 'test';

       // These fields can be assigned a log file path, and will save the
       //  request and response xml data.
       OverrideLineItemReqDS.RequestLog = 'T_OVRLNITM_Request.xml';
       OverrideLineItemReqDS.ResponseLog = 'T_OVRLNITM_Response.xml';

       // These fields are required for all line item transactions.
       OverrideLineItemReqDS.RunningTaxAmount = 0.42;
       OverrideLineItemReqDS.RunningTransAmount = 27.42;
       // This is the ID of the LineItem to be overriden. This must be a line
       //  item that has already been transmitted to the payment device. This
       //  cannot be an OFFER line item.
       OverrideLineItemReqDS.LineItemId = '1';
       OverrideLineItemReqDS.Description = 'New Description';
       OverrideLineItemReqDS.Quantity = 1;
       OverrideLineItemReqDS.UnitPrice = 10;
       OverrideLineItemReqDS.ExtendedPrice = 10;

       // If VFN_OverrideLineItem() returns *Off, it means that an error
       //  occurred as part of the overall communication process, and the
       //  information will be in ErrorDS - ErrorDS.Message is the main field
       //  to look at for troubleshooting.
       if not VFN_OverrideLineItem( OverrideLineItemReqDS
                                  : OverrideLineItemRspDS : ErrorDS );
         // handle error
         WriteToJobLog( 'Message ID: ' + ErrorDS.MessageId + NewLine );
         WriteToJobLog( 'Message: ' + ErrorDS.Message + NewLine );
         *INLR = *On;
         return;
       else;
         WriteToJobLog( 'Response Text: ' + OverrideLineItemRspDS.ResponseText
                      + NewLine);
         WriteToJobLog( 'Result: ' + OverrideLineItemRspDS.Result + NewLine );
         WriteToJobLog( 'Result Code: ' + OverrideLineItemRspDS.ResultCode
                      + NewLine );
         WriteToJobLog( 'Termination Status: '
                      + OverrideLineItemRspDS.TerminationStatus + NewLine );
       endif;

       *INLR = *On;
       return;