>Hi,
> What is ASSERT function used for? I don't understand the desc. from HELP.

ASSERT checks the state of a logical expression while the app is under development, before the applicatrion blows as a result of an unexpected value that you tested for in the logical condition, and will trigger a messagebox with an option to fire up the debugger then and there when run under the Development version of VFP. When installed and running under the runtime environment, the ASSERT doesn't get triggered, so you can leave ASSERTs in the code for debugging purposes without exposing the user to the unanticipated message.

It's a good way to check that you're calling things with the reight data types for parameters, or check values of parameters and then be able to get to the debugger if things don't work as expected.

>Why should we test in a second instance of VFP?

Checking to see if two app instances will survive, and to provide some limited multi-user/conflict resolution testing are a couple of reasons.

> How to do so?

Start VFP more than one time and run the same program.