[Coco] DEF USR and strings?

[Allen Huffman]

> On Oct 29, 2025, at 8:52 PM, Sean Conner via Coco <coco at maltedmedia.com> wrote:
> 
> It was thus said that the Great Bruce Borer once stated:
>> I do not know what can and cannot be done (yet) but can you pass the
>> address (number) of the string and use the pointer in USRn to do what you
>> want?
> 
>  Is the page I linked to:
> 
> 	https://boston.conman.org/2024/11/26.2-3
> 
> not clear enough?  It goes into extensive detail.
> 
>  -spc

This is excellent.

The sad thing is, I’ve seen this page before, but was not working on anything so I didn’t dive too deep.

Your research into these ROM routines is interesting. It sure makes things easy for you to do stuff like:

110 X$ = USR0("ABCXYZ")
120 PRINT X$

I am surprised at how little code is needed thanks to those ROM routines already existing.

With “Getting Started with Extended Color BASIC” they have multiple references to returning a string, but all use VARPTR in them:

Page 201-202:
https://colorcomputerarchive.com/repo/Documents/Manuals/Hardware/Getting Started With Extended Color Basic (Tandy).pdf <https://colorcomputerarchive.com/repo/Documents/Manuals/Hardware/Getting%20Started%20With%20Extended%20Color%20Basic%20(Tandy).pdf>


My original CoCo 1 was upgraded to Extended, so it came with “Getting Started with Color BASIC” and added on “Going Ahead with” I think it was called. Since this is called “Getting Started” it appears a later version added more info, though wrong and missing info that made it useful.

Great work! I had fun diving into this, but could have saved a lot of time had I read your article first!

		— A