>>This has all worked very well for the last 3 years.
>>
>>Today, I needed to troubleshoot the way some of the return values are
>>handled, but I am observing very strange behavior with the parameter I
>>pass by value. For reference, here is the code:
>

>    cMyResult = SPACE(2000)
>    DECLARE INTEGER XC_eXpressLink IN XCClient.DLL INTEGER nHWnd, STRING cParam, STRING @cMyResult 
>    nHWnd = _SCREEN.HWND
>    N = XC_eXpressLink(nHWnd, cTransactionRequest, @cMyResult)
>

>>I am now seeing an issue with cMyResult not being populated in certain scenarios.
>>I am not sure if this is a problem with the .dll or something in VFP.
>
>The coding technique you're using is correct. Allocate local space, pass by reference, if the XC_eXpressLink() function updates that string, it will be reflected back in VFP.
>
>>- If run the program from the command window using DO TEST the cMyResult
>> variable is properly populated with the results.
>>- If I run the exact same program by hitting control+E or the "Run" toolbar button,
>> cMyResult keeps the value it was initialized to.
>>- If I put a set step on in the code and try to observe the cMyResult variable,
>> it is always populated with the results.
>
>I've never seen this happen before.
>
>>In my production code, I am finding that in some screens that launch a
>>payment transaction, the results are being captured and in some they are
>>not. I have not been able to figure out any common denominator for the
>>failed transactions.
>>
>>I have tried on 3 different machines running Windows 8 and Windows 7. I
>>have tried two different version of the XCharge software I am integrating with.
>>I have tried testing my full application in both source code and compiled, and I
>>have experienced the problems in all environments.
>
>Is there a virus on your LAN? On those machines?
>
>>In short, I am baffled, and the provider of the payment integration software
>>is as well.
>>Any thoughts?

Sounds like something is causing the XCClient.DLL to timeout maybe??? That would explain why it works via the debugger after a SET STEP ON.

Paul do you have any more network traffic on your network today than usual? Or anything that could be slowing down your network speeds?