Instr function not case sensitive in LibreOffice basic?

Question

I am writing a function in LibreOffice basic to find position of a character in a string:

REM  *****  BASIC  *****

Const Source = "abcdefghijklmnopwrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

Function GetPos(Char As String) As Integer

GetPos = InStr(Source, Char)

End Function

And I am calling it from spreadsheet using =GetPos("M") or =GetPos("m") from a cell in the spreadsheet. Both are returning 13.

According to the documentation, there is a parameter which is used to specify whether it should be case sensitive or not (0 or 1). If I specify the parameter, I am getting error "Action not supported. Invalid procedure call".

Any idea how to achieve search within string that is case sensitive?

PS: I am using LibreOffice vanilla Version: 5.2.3.5

Answer 1

Eventually I found the answer here

It appears that all optional parameters need to be passed, such as:

Instr(1, Source, Char, 0)