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From: t-atulb@microsoft.UUCP (Atul Butte)
Newsgroups: comp.sys.mac.programmer
Subject: Re: compiling your own Excel(2.2) functions
Keywords: excel call register serial compuserve
Message-ID: <7133@microsoft.UUCP>
Date: 28 Jul 89 02:06:56 GMT
References: <8007@spool.cs.wisc.edu>
Reply-To: t-atulb@microsoft.UUCP (Atul Butte)
Organization: Microsoft Corp., Redmond WA
Lines: 45

In article <8007@spool.cs.wisc.edu> engber@thylacine.CS.WISC.EDU (Mike Engber) writes:
>
>The new version of Excel, 2.2, advertises that you can compile functions
>and import them for use in Excel. Any of the 2.2 owners care to comment?
> - is it documented in the manual (if not how do you get docs)
> - what all is involved 
> - can functions accept/return array arguments
> - can I use LightSpeed Pascal or C or will I need MPW
>
>It sounds like a really nice feature, but I haven't heard anything about it
>except for one sentence in my upgrade letter so I'm suspicious.
>
>-ME

Don't be suspicious; it's true :-)! I have sent sample external routines
to comp.binaries.mac along with the source code used to produce them.

The sample set of external routines is called the Serial Library, and
with it, you can control the serial ports (i.e. a modem) through
an Excel macro. Along with the external routines is a sample macro
using the routines called CompuServe. This macro, given a list of
stock symbols, will log onto CompuServe and download the latest 
information on those stocks.

Documentation for the library is provided in a Word 4.0 formatted file.
The source code is being distributed in another posting.

I'll try to answer your questions:

You can use either MPW or Think C, Pascal or any compiler
to create the external routines. Each external routine 
must be placed in a CODE resource with a unique number and name.
The CALL macro command opens a resource file and loads in the CODE
resource with the given name. The REGISTER command takes the data
returned by the CALL command and uses it to find the address and
parameters for the external routine.

On page 267 of the Functions and Macros book, you will see a list
of parameter types which the external routines can accept and return.
The only array type available is code K: an array of floating point
values.

Atul Butte
Microsoft Corporation
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