XLL Function Naming Issue

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XLL Function Naming Issue

Posts: 2
Joined: 2014-01-09
I have just started work on my first XLL and have run into an issue with XLL function naming.

I have downloaded the MyXLLAddin1 C# example solution and that builds successfully in VS2012, registers and runs fine in Excel 2010.

I then added my own function called EAN8 (the name of the barcode that the function will encode data for) and this produced an error on loading Excel.

Exception Source: AddinExpress.MSO.2005
Exception Type: System.ApplicationException
Exception Message: 'xlfRegister' failed. Function name: EAN8
Exception Target Site: RegisterXlMethod

I initially thought I had an issue with my code but after various tests it seems to be related to the actual function name. My tests have produced the following results.


The above names are using a simple test function as below.

public static string RRR1(object arg)           // FAILS
    return "test";

I canít find a description anywhere specifying what is allowed and what isnít. The problem only seems to happen when a number is at the end of the function name but only when it is in combination with a small number of characters in the function name.

Can you clarify why this is happening and what combination of letters and numbers are allowed. I was hoping to use EAN8 and EAN13 for barcode functions names but these will both fail.

Posted 09 Jan, 2014 04:06:44 Top
Sergey Grischenko

Add-in Express team

Posts: 7234
Joined: 2004-07-05
Hi Roger,

If you use digits at the end of function names, the number of characters should be more or equal 4. I didnít find any description of this issue. But I tested the C++ example from the XLL SDK and it produced the same issue.
Posted 09 Jan, 2014 04:36:48 Top

Posts: 2
Joined: 2014-01-09
Hi Sergey

Thank you for the quick response. Now that I know it is an Excel limitation I can come up with suitable function names.

Posted 09 Jan, 2014 04:49:43 Top
Andrei Smolin

Add-in Express team

Posts: 17945
Joined: 2006-05-11
Hello Roger,

Yes, the issue is an Excel restriction: a cell name cannot be used as a function name. That is, you get the problem because "EAN8" is a valid cell name.

Regards from Belarus (GMT+3),

Andrei Smolin
Add-in Express Team Leader
Posted 09 Jan, 2014 05:30:20 Top