1. Memory allocation crash

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Hi all,

I've been listening in on the Euphoria mailing list for a little while =
now, having been using EU (2.0, the DOS version) to program for fun for =
the past couple of months. I've got a problem that I think might be a =
bug in the interpreter.

I'm writing code to construct and manipulate my own, basic data =
structures in memory (an intellectual exercise, hopefully bearing fruit =
shortly...) I have set up a quick test program to test my =
floating-point-number structure, which is basically based on Euphoria's =
float64_to_atom() and atom_to_float64() functions right now. Apparently, =
allocating space for these structures works fine. But I'm also managing =
an internal, dynamic array of these structures. In the process of =
iterating to (1) allocate space for new float structures and (2) move =
each in memory onto the end of the array, the program crashes. It seems =
as if the CauseWay DOS Extender built into Euphoria chokes for some =
reason (I've attached the cw.err file for the specific errors).

The strange part is, I'm displaying the array after each iteration, and =
everything looks good up until after the 13th float is added (yes, the =
13th) Although the value of the floats is the same throughout the =
program, suddenly two odd numbers pop up on-screen, and then the program =
crashes. Furthermore, if I trace and step through the code starting at =
iteration 13, step through an entire iteration, then let the program =
continue, the two odd numbers still appear, but the program continues to =
the end (and the rest of the values after the odd two are accurate.)

I'm using the unregistered version on a Win95 system, 32MB of RAM, =
Pentium II 233. I plan on registering eventually (particularly if this =
works), but I don't see how the run-time debugging info would help this =
problem. Does anyone have any ideas as to what is going on? Has this =
kind of a problem been identified and addressed in version 2.1? I'm =
hesitant to post the code itself since it's somewhat sizeable, but if =
anyone (Rob, maybe?) wants to examine it for a closer look, I'm willing =
to send it.

ANY help or advice would be greatly appreciated!


=20
Thanks,

Rod Jackson



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2. Re: Memory allocation crash

Rod Jackson writes:
> It seems as if the CauseWay DOS Extender built into Euphoria
> chokes for some reason (I've attached the cw.err file for the
> specific errors).

cw.err files are rarely useful unless you happen to be executing
a machine code program that you have written, and the dumped
register values mean something to you.

The first thing to do in these cases is:

      1. copy euphoria\include\safe.e into the directory
          containing your .ex file
      2. rename safe.e as machine.e in that directory
      3. run your program and see if anything is caught by safe.e
          (now machine.e)

safe.e will catch statements where you have written something
outside the bounds of your allocated memory blocks.
That's a very common reason for getting a CauseWay error.
The safe.e in 2.1 can catch some things that the safe.e in 2.0 can't.

Regards,
     Rob Craig
     Rapid Deployment Software
     http://members.aol.com/FilesEu/

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3. Re: Memory allocation crash

Thanks Rob,

That helped a lot. I should have known to do that, but I'm not that =
familiar with the language yet, and I had forgotten safe.e existed. I =
found the problem in my code and it's been smooth sailing since.

Much appreciated,

Rod Jackson


----------
From:   Robert Craig[SMTP:rds at email.msn.com]
Sent:   Tuesday, January 26, 1999 7:14 PM
To:     EUPHORIA at LISTSERV.MUOHIO.EDU
Subject:        Re: Memory allocation crash

Rod Jackson writes:
> It seems as if the CauseWay DOS Extender built into Euphoria
> chokes for some reason (I've attached the cw.err file for the
> specific errors).

cw.err files are rarely useful unless you happen to be executing
a machine code program that you have written, and the dumped
register values mean something to you.

The first thing to do in these cases is:

      1. copy euphoria\include\safe.e into the directory
          containing your .ex file
      2. rename safe.e as machine.e in that directory
      3. run your program and see if anything is caught by safe.e
          (now machine.e)

safe.e will catch statements where you have written something
outside the bounds of your allocated memory blocks.
That's a very common reason for getting a CauseWay error.
The safe.e in 2.1 can catch some things that the safe.e in 2.0 can't.

Regards,
     Rob Craig
     Rapid Deployment Software
     http://members.aol.com/FilesEu/

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