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Thread: Difference Between 'On Error GoTo 0' And 'On Error GoTo -1'

  1. #1
    Member Transformer's Avatar
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    Lightbulb Difference Between 'On Error GoTo 0' And 'On Error GoTo -1'

    On Error GoTo 0
    It disables the current error handler.So it is used to resume execution normally (without any error handler).

    Code:
    Sub ErrorHandler()
        
        Dim dblValue        As Double
          
        On Error Resume Next
        ThisWorkbook.Worksheets("A").Range("A1") = "Transformer" ' Subscript out of range error will occur if there is no sheet named "A" in the Workbook
        'On Error GoTo 0 'error handler disabled..next error will not be handled.Uncomment the line to check the effect.
        dblValue = 1 / 0 ' Division by Zero error
        MsgBox "Ingnored all the errors."
        
    End Sub
    In above example if one uncomments the line On Error GoTo 0 then it will not handle the error that comes after this statement.

    On Error GoTo -1
    When an error occurs within a procedure, an exception object is created. On Error GoTo -1 is used to set this exception object to nothing.
    If it is not done then next error handler statement (e.g. On Error GoTo errHandler / On Error Resume Next ...) will not work.

    To check the effect of not using it comment the line 'On error GoTo -1' in the snippet given below.

    Code:
    Sub ErrorTest()
        
        Dim dblValue        As Double
          
        On Error GoTo ErrHandler1
        dblValue = 1 / 0
    ErrHandler1:
        MsgBox "Exception Caught"
        On Error GoTo -1           'Comment this line to check the effect
        On Error GoTo ErrHandler2
        dblValue = 1 / 0
    ErrHandler2:
        MsgBox "Again caught it."
            
    End Sub
    But if you use Resume Next as an error handler then an exception object is not created.

    Code:
    Sub ErrorTest()
        
        Dim dblValue        As Double
          
        On Error Resume Next
        dblValue = 1 / 0
        MsgBox "Exception Caught"
        On Error GoTo ErrHandler
        dblValue = 1 / 0
        'No need to set exception object to nothing as it has not been created
    ErrHandler:
        MsgBox "Again caught it."
            
    End Sub
    More examples to understand the same.


    Code:
    Sub ErrorTestUserHandler()
        
        Dim dblValue        As Double
       
            For lngloop = 1 To 10
                On Error GoTo ErrHandler
                dblValue = 1 / 0
    ErrHandler:
                MsgBox "Caught it."
                On Error GoTo -1 'Comment this line and run it again to see the effect
            Next
            
    End Sub

    Code:
    Sub ErrorTestResumeNext()
        
        Dim dblValue        As Double
       
            For lngloop = 1 To 10
                On Error Resume Next
                dblValue = 1 / 0
                MsgBox "Caught it."
                'No need to set exception object to nothing as it has not been created
            Next
            
    End Sub
    Last edited by Transformer; 04-14-2013 at 12:02 PM.
    Regards,

    Transformer

  2. #2
    Senior Member LalitPandey87's Avatar
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    Nice explanation buddy. Really helps us to understand why and how to use error handling in VBA.

  3. #3
    Administrator Excel Fox's Avatar
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  4. #4
    Senior Member LalitPandey87's Avatar
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    To the point explanation. Before this i also don't even know the use of on error goto -1 and now my confusion is clear. thanks excelfox and transformer.
    Last edited by LalitPandey87; 04-11-2013 at 08:55 PM.

  5. #5
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    Finally I found an explanation for GoTo 0 that I could understand.
    The GoTo -1 and the no exception object with Resume Next made it a 10 out of 10 post.
    Thanks so much for posting this!!!

  6. #6
    Fuhrer, Vierte Reich DocAElstein's Avatar
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    Quote Originally Posted by skywriter View Post
    .... the no exception object with Resume Next made it a 10 out of 10 .....
    ... Agreed. That jem of info was the bit missing by me...now I see ( I think ) why despite an error "occuring", ( andbeing "Handeled by the Resume Next ) I can follow it by enabling another error handler without resetting the exception-- in the case of Resume Next I see now there is no acception raised. It had been explained to me as "surpressing the errror", which I read as something else.. ( not quite sure what - I was puzzeled ) - now I understand ( I think! )

    Thanks for Sharing

    Alan

  7. #7
    Fuhrer, Vierte Reich DocAElstein's Avatar
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    .
    . Hi,
    . A Couple of follow up questions.

    . 1 ) Would you describe On Error GoTo 0 and On Error GoTo -1 as error statements,
    And
    . 2 ) On Error Resume Next and On Error GoTo some_label/line_number as error handlers.
    . Thus we have in VBA 2 types of “error handlers”. I ask as the literature is often confusing, ( possibly caused partly by the GoTo 0 and GoTo -1 which do not actually “go anywhere” I believe ).
    . One is often mislead in thinking in terms of 4 “error handlers”

    Thanks
    Alan
    Last edited by DocAElstein; 05-27-2015 at 08:55 PM. Reason: Editor lost some spaces between words!!??

  8. #8
    Fuhrer, Vierte Reich DocAElstein's Avatar
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    P.s. Just for info: Similar Blog is here
    On Error WTF? | Excel Matters

    Edit April 2018
    Also see here:
    http://www.excelfox.com/forum/showth...GoRoT-N0Nula-1
    Last edited by DocAElstein; 05-07-2018 at 02:06 PM.

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