Question

I have the following Sub:

Public Function Log(sdsMessage As CStandardPropertySet2)
' Only print the fields contained int he sdsMessage
End Function

and I use it like this:

Log(anSdsMessage)

However this results in the Argument not optional error.

But if I have the sub like this:

Public Function Log(sdsMessage As CStandardPropertySet2) As CStandardPropertySet2
' Only print the fields contained int he sdsMessage
Set Log = sdsMessage
End Function

Set anSdsMessage = Log(anSdsMessage)

Then the error disappears. This looks very awkward to me as I do not need to modify the message at all and only want to print the fields in it.

Could someone please tell me what I am doing wrong?

Answer 1

This is silly confusing VBA syntax. when you are jsut calling Log as a method and have no return type you omit the parentheses.

so Log anSdsMessage when no return value is set

and (correctly as you have it already) Set anSdsMessage = Log(anSdsMessage) when a return value is set.

To address Daniel’s comment

I can write this code

Public Function Log(sdsMessage As Collection)
' Only print the fields contained int he sdsMessage
End Function

Sub tester()
    Dim o As Collection
    Set o = New Collection
    Log (o)
End Sub

And try to run the tester sub and I get the error message “Compile error: Argument not optional”

Removing the parentheses and running Log o does in fact allow compilation and removes the error.