If a call to any GSCP results in an error being flagged, control passes to a 4GL procedure named iiappsvrErrorTrap. This can be overridden by a user procedure of the same name in which further error processing, logging, and so on, can be performed.

Situations that cause an error to be flagged include execution of the EXIT 4GL statement, a runtime error, or execution of the OSCA.ReturnWithUserError and OSCA.ReturnWithFatalError methods.

The three container procedures described should be implemented as regular 4GL procedures with no return type declared. You should design them carefully so they do not become a performance bottleneck. In a production environment, for example, it should be possible to remove or disable container functionality that assists in development and testing.