FINALLY
You can use the TRY…CATCH…FINALLY statements for structured exception handling. This allows you to execute a particular block of statements if a specified exception occurs while your code is running. When this happens, the code is said to THROW the exception, and you catch it with the appropriate CATCH command.
FINALLY
Remarks
The TRY statements are executed first. If no exception occurs, execution continues after the ENDTRY.
If an exception occurs, then the systems tries to match the exception to the exception types in the FINALLY commands. The first one that matches causes the exception to be “trapped” and the catch statements in the matched FINALLY to be executed. If the exception is trapped by a FINALLY then after the catch statements are executed, control goes to the next statement after the ENDTRY .
If a FINALLY command is present, then the finally statements will always be executed at the end of the TRY/CATCH sequence or TRY /untrapped exception, no matter what.
Rules:
- The only branching commands allowed inside a TRY/CATCH block are ITERATE, and LEAVESR. Any other branching command (CAB, GOTO, etc.) is not allowed in this context. It is also illegal to branch out of a FINALLY clause (i.e., you cannot use any of the branching commands (ITERATE, CAB, LEAVESR, GOTO, etc) in the body of a FINALLY clause.
- The exception Type MUST derive from System.Exception (the mother of all exceptions). A CATCH with a System.Exception type will trap all exceptions.
- If you have several CATCH commands, the Name must be different at this time.
Example
BEGSR TryCatch access(*public)
Dclfld myFld Type(System.Windows.Forms.Button)
Dclfld myInt *integer 4
TRY
myFld.Show()
myInt = myInt / 0
CATCH name( z ) type( System.DivideByZeroException )
msgbox msg( "by 0" ) Title( z.Message )
CATCH name( e ) type( System.Exception )
msgbox msg( "You can't do that!!!" ) Title( e.Message )
**FINALLY**
msgbox "Wow, this works..."
ENDTRY
msgbox "All is well!"
ENDSR