Error System¶

Include: Use System\ErrorSystem.pkg

The Error System routes runtime errors to an error handler. Local Try/Catch blocks let code handle a reported error around a protected block, while the Error command creates and reports an error through the Error System.

Topics¶

Try/Catch - Handles errors reported while a protected block runs.

Handler¶

cBaseErrorHandler - Base error handler class.

Globals¶

Error - Signals an error to the Error System.
UserError - Raises a user-facing error.
Error numbers - Grouped DFERR_* constants.

Try/Catch and Error¶

Construct	Use it when	What it does
Try/Catch	Code can recover from, translate, clean up after, or re-raise an error from a block.	Runs protected code and transfers control to `Catch` if an error is reported inside the block.
`Error`	Code detects an invalid condition and needs to report it as an Error System error.	Raises/reports the supplied error number and optional text through the Error System.

Try/Catch does not create an error by itself; it handles an error raised by runtime code, package code, or an explicit Error command.

Error does not recover from anything; it reports the error, so use it at the point where the invalid condition is detected.

A Catch block may handle the error locally or re-raise/report an error again when callers still need to see it. For example, transaction commands clean up and use Error Last_Error_Number ErrText so the caller's error handler still sees the error.

For the full protected-block flow and Catch variable forms, see Try/Catch.

Example¶

Procedure SaveCustomer String sCustomerName
    Try
        If (sCustomerName = "") Begin
            Error DFERR_OPERATOR "Customer name is required."
        End

        Send DoSaveCustomer sCustomerName
    Catch
        Send UserError ErrText "Save failed"
    End_Try
End_Procedure

The Error command reports the invalid empty name; Catch handles any error from the guarded block and converts it to a user-facing message.