How to get the procedure or function name at runtime?

I am not quite sure how helpful this is going to be…

The good thing is that you will not have to worry about the sub/function name – you are free to change it. All you have to care about is the uniqueness of the error handler label name.

For example

if you can avoid duplicate error handler labels in different subs/functions

don’t do ⇩⇩⇩⇩⇩

Sub Main()
    On Error GoTo ErrHandler
    Debug.Print 1 / 0

ErrHandler:
    Debug.Print "handling error in Main"
    SubMain
End Sub

Sub SubMain()
    On Error GoTo ErrHandler
    Debug.Print 1 / 0

ErrHandler:
    Debug.Print "handling error in SubMain"
End Sub

then the below code should work.

Note: I haven’t been able to test it thoroughly but I am sure you can tweak it and get it work if it’s of any help.

Note: Add references to Visual Basic for Applications Extensibility 5.3 via Tools -> References in VBE

Sub Main()

    ' additionally, this is what else you should do:
    ' write a Boolean function that checks if there are no duplicate error handler labels
    ' this will ensure you don't get a wrong sub/fn name returned

    Foo
    Boo

End Sub


Function Foo()

    ' remember to set the label name (handlerLabel) in the handler
    ' each handler label should be unique to avoid errors
    On Error GoTo FooErr
    Cells(0, 1) = vbNullString ' cause error deliberately

FooErr:

    Dim handlerLabel$
    handlerLabel = "FooErr" ' or don't dim this and pass the errHandler name directly to the GetFnOrSubName function

    Debug.Print "Error occured in " & Application.VBE.ActiveCodePane.CodeModule.Name & ": " & GetFnOrSubName(handlerLabel)

End Function


Sub Boo()

    On Error GoTo BooErr
    Cells(0, 1) = vbNullString ' cause error deliberately

BooErr:

    Debug.Print "Error occured in " & Application.VBE.ActiveCodePane.CodeModule.Name & ": " & GetFnOrSubName("BooErr")

End Sub

' returns CodeModule reference needed in the GetFnOrSubName fn
Private Function GetCodeModule(codeModuleName As String) As VBIDE.CodeModule
    Dim VBProj As VBIDE.VBProject
    Dim VBComp As VBIDE.VBComponent

    Set VBProj = ThisWorkbook.VBProject
    Set VBComp = VBProj.VBComponents(codeModuleName)

    Set GetCodeModule = VBComp.CodeModule
End Function

' returns the name of the sub where the error occured
Private Function GetFnOrSubName$(handlerLabel$)

    Dim VBProj As VBIDE.VBProject
    Dim VBComp As VBIDE.VBComponent
    Dim CodeMod As VBIDE.CodeModule

    Set VBProj = ThisWorkbook.VBProject
    Set VBComp = VBProj.VBComponents(Application.VBE.ActiveCodePane.CodeModule.Name)
    Set CodeMod = VBComp.CodeModule

    Dim code$
    code = CodeMod.Lines(1, CodeMod.CountOfLines)

    Dim handlerAt&
    handlerAt = InStr(1, code, handlerLabel, vbTextCompare)

    If handlerAt Then

        Dim isFunction&
        Dim isSub&

        isFunction = InStrRev(Mid$(code, 1, handlerAt), "Function", -1, vbTextCompare)
        isSub = InStrRev(Mid$(code, 1, handlerAt), "Sub", -1, vbTextCompare)

        If isFunction > isSub Then
            ' it's a function
            GetFnOrSubName = Split(Mid$(code, isFunction, 40), "(")(0)
        Else
            ' it's a sub
            GetFnOrSubName = Split(Mid$(code, isSub, 40), "(")(0)
        End If

    End If

End Function