>Thanks Christof. Now that suggests that there is some mechanism to 'inform' the desired callbacker to do so. Would it be a discrete 'function' or some option of the parameter list or???
>

As George points out, the callback function is identified in the API call (or set up in a call that preceded and set up the desired function call.) It's a reference to a place in code, not a p-code reference point. The most common practice in the past with accessing APIs that require callbacks to VFP has been to write an FLL to provide the callback entrypoint and invoke the API call through the FLL.

>Jim N
>
>>Hi Jim,
>>
>>>Could one of you inform the poorly educated among us (that's me at least) of what a "callback is?? I would appreciate it.
>>
>>A callback means that Windows (or any other DLL) calls a function in your VFP application when something happens.
>>
>>Christof