[BASIC] Bug make system freeze when source code is "big"

Hello

As the application I am writing is growing, the need to split it in different “modules” became insistent.
So, I split the application into several files: a BASIC !RunImage file using LIBRARY to load three other BASIC files.
Since then, I noted that any bug introduced in the source code causes the system to freeze, instead of the error message notifying the file and the line where the bug occured.
Debugging my application is now become an nightmare as I have to reboot my RiscOS computer at every single error, even for basic error like function name mispelled.

As i thought this was caused by the split in different files, I came back to the situation where the !RunImage contains the whole source code… to discover, horrified, that this did not help…

It is as if the application has become too big for BASIC to handle error “properly”!

NOTE: due to the specifity of the application, I run it in BASIC VI (for 64bits floating number)

Please, I desperately need help!

Thank you very much.

François

I think it is extremely unlikely that the program is too big. If you attempt to load it, or its libraries, into a wimp slot that is too small you will get an error before anything dangerous happens.

Your description is very brief. When you say the system freezes, is that completely, or do Alt_Break or Ctrl_Break work? Are you doing any indirected memory accesses that could overwrite other parts of the system? Is there any assembler? It occurs to me that you could check how your error handling routine works. If you don’t have ON ERROR OFF you could get into a loop, but that should respond to Alt-Break.

Any more detail, such as the version of BASIC VI, would make help easier, but I’m afraid it is something in the program, rather than a limitation of BASIC.

As Steve says – it is unlikely to be BASIC. The more probable cause is something went askew when the program was split up.

The first thing to try:

• Have you used assembler anywhere?
• Do you have indirection ( blah%!something% )?

If so, comment out the code (a quick’n’dirty way if it is big is to wrap it in IF TRUE=FALSE THEN … ENDIF so it won’t get executed).
Does your program work now?

If Alt-Break works so you can abort your program, try using:
TRACE TO "<filename>"
TRACE PROC
to get BASIC to report procedures as they are entered. This won’t give the exact line of failure, but it should provide a pointer as to where to look.
If you need a better pointer, then use:
TRACE ON
but note that it can be pretty unwieldy!

If your program does stiff the machine (so nothing permits access to the OS) then your best bet is to write a routine to pop up a Wimp_ReportError box; then just call this with a different letter of the alphabet at checkpoints within your program (so you can click past A, B, C, D, and the machine freezes before it gets to E).
Just – take my experience – you do NOT want to put a checkpoint inside a loop that goes around dozens/hundreds of times! If you suspect the loop, put a checkpoint either side of it, not inside it! ;-)

Something like this:

PROCcheckpoint("a")
PROCdo_task_init_stuff
PROCcheckpoint("b")
PROCload_interesting_files
PROCcheckpoint("c")
[etc]


DEFPROCcheckpoint(msg$)
  REM ** ASSUMES "wimp%" is the name of your 256 byte block
  REM **         that you use with Wimp SWIs (Poll, etc).
  REM **         If not, amend as necessary; not NOTE that
  REM **         things could mess up if you put a checkpoint
  REM **         in a place where you are USING the Wimp data
  REM **         block; like Poll handler, event handler, etc.
  wimp%!0    = 0
  $(wimp%+4) = msg$+CHR$(0)
  SYS "Wimp_ReportError", %10011001, "debug"
ENDPROC

T’was simpler on my A5000, I could just TRACE TO “serial:$.meh” and watch the output on an old VT110 terminal hooked up to the serial port. ;-)

What do you call ‘big’? I regularly run a Basic program with about 30,000 lines, with about 30 libraries. It does error from time to time(!), and I have not had lockups as you describe.

But I do use Reporter for debugging!

Hi

I thank you all warmly for your answers.
Of course, I beleive the issue is in my code and “big” is not actually big… but the behaviour is so weird.
I didn’t know about Reporter. I think i will look at it closely.

I will keep you inform. I might drop the code somewhere on the net for download if i continue to be stuck.

Cheers

François

Hello

Thank you for the alt-break tip… it indeed helped a lot and solved my problem of rebooting…
And Reporter is a real gem! Fantastic tool that will surely become my best friend for programming!