You would pass it on the second parameter, which is basically for a long explanation of the error. AERROR() info could be included in the exception source parameter.

But you are right, the client app needs to be expecting it, otherwise the user would just go Huh?

>>Actually you can use ComReturnError() to relay the XML error information back to a COM client. This function was added specifically for improved COM support on errors and is certainly appropriate in this situation.
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>Hmmm, I woudln't recommend that though. If some COM object did that in my apps, I'd have no idea what do with it. Its all up to the client, and thats why there's the standard error structure.
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>Though, being able to return TRAPPED (expected) errors safely from a COM object's method is not a bad idea, I do it often.
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>>Although the help files do not specify if there is a limit to the amount of info you can pass back through it.
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>I've seen wild things doing that. In VFP7 I got alot of C5 errors, in VFP6 things like "?" would stop working from the command window. Kindof wierd.