Error state handler

During the execution of script actions, various error states may occur, which are normally handled by terminating the script and writing a log to the log database. Such a log contains the line number where the error occurred, error code and, for some specific error types, also extended description. Error code is a value of one of predefined local variables (constants) which begins with ERR_*.

The exceptions in ESL may be controlled in two ways:

• ON ERROR actions
• EXCEPTION_HANDLER

The first method activates an error handling by ON ERROR action. The action defines label where the handler (ESL script actions) is placed. This handling method is variable but if it is used incorrectly it can not provide an easy survey and can be misleading.
The second method is more easy and clear. EXCEPTION_HANDLER action defines the place where the handler is being occurred within a procedure and defines whether the errors are handled.