VBScript -- Using error handling

Question

I want to use VBScript to catch errors and log them (ie on error "log something") then resume the next line of the script.

For example,

 On Error Resume Next 'Do Step 1 'Do Step 2 'Do Step 3 

When an error occurs on step 1, I want it to log that error (or perform other custom functions with it) then resume at step 2. Is this possible? and how can I implement it?

EDIT: Can I do something like this?

 On Error Resume myErrCatch 'Do step 1 'Do step 2 'Do step 3  myErrCatch: 'log error Resume Next 

Answer 1

VBScript has no notion of throwing or catching exceptions, but the runtime provides a global Err object that contains the results of the last operation performed. You have to explicitly check whether the Err.Number property is non-zero after each operation.

On Error Resume Next  DoStep1  If Err.Number <> 0 Then   WScript.Echo "Error in DoStep1: " & Err.Description   Err.Clear End If  DoStep2  If Err.Number <> 0 Then   WScript.Echo "Error in DoStop2:" & Err.Description   Err.Clear End If  'If you no longer want to continue following an error after that block's completed, 'call this. On Error Goto 0 

The "On Error Goto [label]" syntax is supported by Visual Basic and Visual Basic for Applications (VBA), but VBScript doesn't support this language feature so you have to use On Error Resume Next as described above.

Answer 2

Note that On Error Resume Next is not set globally. You can put your unsafe part of code eg into a function, which will interrupted immediately if error occurs, and call this function from sub containing precedent OERN statement.

ErrCatch()  Sub ErrCatch()     Dim Res, CurrentStep      On Error Resume Next      Res = UnSafeCode(20, CurrentStep)     MsgBox "ErrStep " & CurrentStep & vbCrLf & Err.Description  End Sub  Function UnSafeCode(Arg, ErrStep)      ErrStep = 1     UnSafeCode = 1 / (Arg - 10)      ErrStep = 2     UnSafeCode = 1 / (Arg - 20)      ErrStep = 3     UnSafeCode = 1 / (Arg - 30)      ErrStep = 0 End Function