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COM error handling in a UDF - best practice?

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orbs

COM error handling is a global thing, right? when i declare this:

$oCOMError = ObjEvent('AutoIt.Error', '_COMErrorHandler')

it means that whatever previous declaration i made for "AutoIt.Error" is discarded.

now, suppose i write a UDF that uses COM, and i want to introduce COM error handling in the UDF. i do just that, but then, the main script declares a COM error handler for its own purposes, that is unaware of the UDF COM error handler. this means the UDF COM error handler is discarded.

how to approach such a situation, when i want the UDF COM error handler to not interfere with the main script COM error handler, but still operate?

thanks for any ideas.

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mLipok

Look in my ADO and XML udf.

HINT: You should declare COM ERROR HANDLER in UDF locally for each function.

 

Edited by mLipok

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orbs

let me see if i get this right:

the main script can define a dedicated function, which resides in the main script, that will handle COM error in the ADO UDF. the ADO UDF error handler, which is not declared globally but at the beginning of every UDF function (thus revoked once the function had returned), will call the main script dedicated function if declared, otherwise will call the UDF default COM error handler.

if so, how should the main script declare a COM error handler for COM operations not related to the UDF?

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water

Example:
You define a global COM error handler to grab all COM errors occurring in the main script. A local COM error handler grabs all COM errors occurring inside a function.
When  the function ends the local COM error handler is dropped and the global COM error handler is active again.

Global $oGlobalCOMErrorHandler = ObjEvent("AutoIt.Error", "_ErrFuncGlobal") ; Global COM error handler

Global $oIE = ObjCreate("InternetExplorer.Application")
$oIE.xyz
FunctionLocal()
$oIE.xyz
Exit

Func FunctionLocal()
    Local $oLocalCOMErrorHandler = ObjEvent("AutoIt.Error", "_ErrFuncLocal") ; Local COM error handler
    $oIE.xyz
EndFunc

; Global COM error handler
Func _ErrFuncGlobal($oError)
    ; Do anything here.
    ConsoleWrite(@ScriptName & " (" & $oError.scriptline & ") : ==> Global COM error handler - COM Error intercepted !" & @CRLF & _
            @TAB & "err.number is: " & @TAB & @TAB & "0x" & Hex($oError.number) & @CRLF & _
            @TAB & "err.windescription:" & @TAB & $oError.windescription & @CRLF & _
            @TAB & "err.description is: " & @TAB & $oError.description & @CRLF & _
            @TAB & "err.source is: " & @TAB & @TAB & $oError.source & @CRLF & _
            @TAB & "err.helpfile is: " & @TAB & $oError.helpfile & @CRLF & _
            @TAB & "err.helpcontext is: " & @TAB & $oError.helpcontext & @CRLF & _
            @TAB & "err.lastdllerror is: " & @TAB & $oError.lastdllerror & @CRLF & _
            @TAB & "err.scriptline is: " & @TAB & $oError.scriptline & @CRLF & _
            @TAB & "err.retcode is: " & @TAB & "0x" & Hex($oError.retcode) & @CRLF & @CRLF)
EndFunc   ;==>_ErrFunc

; Local COM error handler
Func _ErrFuncLocal($oError)
    ; Do anything here.
    ConsoleWrite(@ScriptName & " (" & $oError.scriptline & ") : ==> Local COM error handler - COM Error intercepted !" & @CRLF & _
            @TAB & "err.number is: " & @TAB & @TAB & "0x" & Hex($oError.number) & @CRLF & _
            @TAB & "err.windescription:" & @TAB & $oError.windescription & @CRLF & _
            @TAB & "err.description is: " & @TAB & $oError.description & @CRLF & _
            @TAB & "err.source is: " & @TAB & @TAB & $oError.source & @CRLF & _
            @TAB & "err.helpfile is: " & @TAB & $oError.helpfile & @CRLF & _
            @TAB & "err.helpcontext is: " & @TAB & $oError.helpcontext & @CRLF & _
            @TAB & "err.lastdllerror is: " & @TAB & $oError.lastdllerror & @CRLF & _
            @TAB & "err.scriptline is: " & @TAB & $oError.scriptline & @CRLF & _
            @TAB & "err.retcode is: " & @TAB & "0x" & Hex($oError.retcode) & @CRLF & @CRLF)
EndFunc   ;==>_ErrFunc

 

Edited by water
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orbs

oh, i see what i was missing. the error handler functions accept a parameter! and that parameter is assigned with the error object that was declared in the corresponding ObjEvent() command. not so obvious, but now it makes sense. thanks (again...) @water

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water

;)


My UDFs and Tutorials:

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ExcelChart (2015-04-01 - Version 0.4.0.0) - Download - General Help & Support - Example Scripts
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PowerPoint (2015-06-06 - Version 0.0.5.0) - Download - General Help & Support

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