XFN and HP71B



I'm trying to run a basic program on the HP71 and anytime I run it, it says ERR Lxxx:XFN not found! Could you tell me what "XFN" is? I'm beginner with the 71! Any help appreciated, Thanks in advance


The XFNxxxyyy is a so-called eXtendedFunctioN coming from a LEX-file (Language Extension file). There are also XWORDs in LEX-Fuiles.

An XWORD is a command or statement like DISP A$; an XFN is a function like SIN(A).

Each LEX-File has its own ID xxx and the fcn no. yyy, so they are pretty compatible altogether and do not collide. HP used to give the xxx numbers to different parties, who registered with HP.

Interesting note: The internal functions and commands of the 71 are also XFNs and XWORDs with the LEX ID 0 and 1.

If you can email the XFN value missed, I could search for the function (and the LEX file) and email it to you.

You should simply edit the line, where the error occurs, then you know the XFNxxxyyy.

I have a 16 years experience on the 71, so I should be able to help you

BTW: did you sell some HP-41 IL modules on eBay? I won one auction, but I didn't get a response to my email til now. If you are the seller, you might expect some money from me. Please notify me.


Reinhard you're great! I think I understood. The files I was looking for was XFN240003 : which means in hex F0/03 and according to joe horn's lexicon gives the lex file named "textutil" Am I right?

Thanks in advance, once again!


I was wrong : it's FILESZR$ which can be obtained by EDLEX or TEXTUTIL...


I can't check this right now. The best test is loading one of the files into the calculator and checking it out.

I once tried to load all the LEX files I knew into my 71 (+96k RAM expansion).

The thing got real slow and unstable (just imagine checking all the poll handlers when pressing a key).

Don't try this at home :-)

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