I am just starting to dig into the DCS SDK and these two pages caught my eye.

http://dcs.cemetech.net/index.php/BasicLibs:BinRead

http://dcs.cemetech.net/index.php/BasicLibs:BinDelete

BinRead takes data from a "FILENAME", I assume that only means .8xp filenames since it didn't work with an appvar name. I am wondering why it allows negative values for the start byte and allows the arguments to go past the end of the file. It's not too important since security isn't a concern on a calculator, but there all kinds of weird things that this entails, which I'll describe in a second. BinDelete is worse, again it allows negative arguments and it can will accept arguments that make go past the end of the file, which is an actual problem since this means you can crash the calculator very easily, as I did.

The weird things I mentioned earlier:

1. Since you can give BinRead nonsensical arguments, I tried 10^96, 10^97 etc, with various arguments for the length. They all returned the same predefined section of a string only varying based on the length argument.

2. They accept non-integer arguments for the starting byte and the length of the returned string. For BinRead with 0 as the start byte, and .999 for the length, I got a memory error. For .599 as the length I got a long stream of flowing tokens and ASCII before it crashed.

3. For a nonexistent program file, BinRead writes ".7" to ANS and ".6" for a blank string as the filename, which isn't on the SDK page.

4. From BinRead I have gotten ".L" when I gave the imaginary unit as the argument for the start byte, and 1, for the length.

5. For BinRead and BinDelete, I gave i, the imaginary unit as the arguments for the start byte and the number of bytes and it archived the program I gave as the filename.

I could go on, but I think this is enough.

http://dcs.cemetech.net is formatted like a wiki, but I can't seem to find anyway to edit. What I would like to do is dive into the DCS source code help document it, since all of the pages seem pretty sparce.

If anyone can explain why these "functions" act so weirdly instead of just giving error messages, I would love to hear it. Otherwise I'd like to ask if there is a way to edit pages on http://dcs.cemetech.net

Incorrect. Via the parent page:
It's the programmer's responsibility to provide sane arguments here; some safety checks are performed, but others are not to give programmers more flexibility.

Welcome to dumping random memory.

These are error codes. See the original Celtic 3 documentation for the definitions of these "short" error codes. You can get the long error codes from the output string.

Fun! I consider none of these bug reports, but it's an interesting investigation into what these functions do with invalid arguments.

Unless Tari disconnected it, it's linked to Cemetech user credentials, so you should be able to log in with those.

Okay, thanks for the clarification Kerm. I disagree that it is the job of the programmer who is making a mobile app etc to do input validation though. If that were the case for computer programming then it would be much easier to write exploits and steal personal info from people. Since that's not a concern here, I think it makes sense to have safety checks at least for BinDelete since you can easily crash the calculator.

Do you have an explanation for #5 though, I didn't see anything about archival in the other libraries, but maybe I just need to look harder?

BTW I'm enjoying your book right now. (: