OpenEuphoria

1. How come: crash/no crash?

• Posted by Al Getz <Xaxo at aol.com> Dec 28, 2005
• 438 views
• Last edited Dec 29, 2005

Hello,

Recently i was working with a program that uses the Win API and a 
point structure.  In my haste, i allocated the point struct
incorrectly as:

ppt=allocate(4) --should be at least (8)

The point struct was then used in a Win API call which loads it:

  retv=winapi_function_call(ppt)

then the result is read into a sequence with peek's.

Strange thing is, under Win XP Pro (sp1 OR sp2) the above code
*NEVER* crashed, while under XP Home it *ALWAYS* crashed.

When i say 'it crashed' i mean a Euphoria machine exception error
is generated and the program halts.  When it doesnt crash the
program works normally exactly as expected with no complains (XP Pro).
In both cases the program has been bound (exe), but in the XP Pro case
the .exw file doesnt crash nor the bound exe file either.

Im asking about this because if you go through the trouble of
troubleshooting the program and it runs fine with no errors, then
you run it under XP Home and it doesnt work, that's nasty.

Any ideas, anyone?



Take care,
Al

And, good luck with your Euphoria programming!

My bumper sticker: "I brake for LED's"

3. Re: How come: crash/no crash?

• Posted by Al Getz <Xaxo at aol.com> Dec 28, 2005
• 424 views
• Last edited Dec 29, 2005

Bernie Ryan wrote:
> 
> Al Getz wrote:
> > 
> > Hello,
> > 
> > Recently i was working with a program that uses the Win API and a 
> > point structure.  In my haste, i allocated the point struct
> > incorrectly as:
> > 
> > ppt=allocate(4) --should be at least (8)
> > 
> > The point struct was then used in a Win API call which loads it:
> > 
> >   retv=winapi_function_call(ppt)
> > 
> > then the result is read into a sequence with peek's.
> > 
> > Strange thing is, under Win XP Pro (sp1 OR sp2) the above code
> > *NEVER* crashed, while under XP Home it *ALWAYS* crashed.
> 
> 
> Al:
>   What probably is happening is when XP Pro runs the program it runs
>   the program in memory where there is a spot in memory that is
>   has nothing located in it. so it just overwrites those
>   extra locations.
> 
>   When you use XP Home the program is writing over a protected area
>   that is being used by the OS.
>  
> Bernie
> 
> My files in archive:
> w32engin.ew mixedlib.e eu_engin.e win32eru.exw
> 
> Can be downloaded here:
> <a
> href="http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan">http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan</a>

Hi Bernie,


Yes, that's probably it :)
Win XP Pro probably allocated more memory than Home did so it didnt trigger
an error, but this is BS if you ask me.  I think they should both work
the same or at least XP Pro should have triggered the error too, because
this program was considered "fully tested" before shipping and when someone
ran it on Home it crashed right away...that's just nuts.  I ran this program
many times on my own machine too which told me it was working.
How can we stamp a program "Fully tested" if there's a bug in it that
doesnt show up sometimes?  That's lousy if you ask me.  I understand
it's the fault of Windows and not Euphoria too.
So the mem manager of XP Pro must be different than the mem manager
of XP Home...strange if you ask me.  There are enough reasons not to
like Windows, i didnt need another one (hee hee).


Take care,
Al

And, good luck with your Euphoria programming!

My bumper sticker: "I brake for LED's"

5. Re: How come: crash/no crash?

• Posted by Matt Lewis <matthewwalkerlewis at gmail.com> Dec 29, 2005
• 425 views

Al Getz wrote:
> 
> Yes, that's probably it :)
> Win XP Pro probably allocated more memory than Home did so it didnt trigger
> an error, but this is BS if you ask me.  I think they should both work
> the same or at least XP Pro should have triggered the error too, because
> this program was considered "fully tested" before shipping and when someone
> ran it on Home it crashed right away...that's just nuts.  I ran this program
> many times on my own machine too which told me it was working.
> How can we stamp a program "Fully tested" if there's a bug in it that
> doesnt show up sometimes?  That's lousy if you ask me.  I understand
> it's the fault of Windows and not Euphoria too.
> So the mem manager of XP Pro must be different than the mem manager
> of XP Home...strange if you ask me.  There are enough reasons not to
> like Windows, i didnt need another one (hee hee).
> 

Well, I could argue that your program wasn't 'fully tested' since you didn't
test against safe.e, which presumably would have caught your problem, since
you would have read from memory you didn't allocate.

Matt Lewis

7. Re: How come: crash/no crash?

• Posted by Pete Lomax <petelomax at blueyonder.co.uk> Dec 29, 2005
• 437 views

On Wed, 28 Dec 2005 12:58:33 -0800, Al Getz <guest at RapidEuphoria.com>
wrote:

>Recently i was working with a program that uses the Win API and a 
>point structure.  In my haste, i allocated the point struct
>incorrectly as:
>
>ppt=allocate(4) --should be at least (8)
>
>Strange thing is, under Win XP Pro (sp1 OR sp2) the above code
>*NEVER* crashed, while under XP Home it *ALWAYS* crashed.

Does machine.e/safe.e catch this?

>Im asking about this because if you go through the trouble of
>troubleshooting the program and it runs fine with no errors, then
>you run it under XP Home and it doesnt work, that's nasty.

True. There is, I feel, a valid argument perhaps that if you have:

with trace
include machine.e

ie trace is on, and machine.e has not already been included, it should
say 'fek it - use safe.e', and ignore any subsequent include machine.e

Regards,
Pete

9. Re: How come: crash/no crash?

• Posted by C Bouzy <eucoder at hotmail.com> Dec 29, 2005
• 422 views

Brian Broker wrote:

> It's certainly not fair to blame any OS for programming mistakes.  However,
> it may not be a programming mistake at all.  The system that's crashing may
> have DEP enabled and that will generate a machine-level exception by just
> running
> Euphoria's own Win32 demo programs.
> 
> DEP is Data Execution Prevention.  To check the settings, open the System
> control
> panel, click the Advanced tab, click Performance settings button, click Data
> Execution Prevention tab.  If you don't want Euphoria to crash, you should
> either
> have the first radio selected (turn on DEP for essential Windows programs and
> services only) or you will need to create an exception for your program if the
> second radio is selected (turn on DEP for all programs and services except
> those
> I select).
> 
> I recently ran into this issue again and it was nearly impossible to debug.
> 
> -- Brian

Disabling DEP is not a good idea, your app should run with it on. DEP is
used to prevent viruses from running malicious code from memory locations,
and almost every XP computer with Service Pack 2 installed will have this
enabled by default. You cannot tell every user who wants to run your
app to disable DEP.


----If you continue to do what you have always done,
you will get what you have always gotten.----

11. Re: How come: crash/no crash?

• Posted by Brian Broker <brian_broker at yahoo.com> Dec 29, 2005
• 442 views

C Bouzy wrote:
> 
> Brian Broker wrote:
> 
> > It's certainly not fair to blame any OS for programming mistakes.  However,
> > it may not be a programming mistake at all.  The system that's crashing may
> > have DEP enabled and that will generate a machine-level exception by just
> > running
> > Euphoria's own Win32 demo programs.
> > 
> > DEP is Data Execution Prevention.  To check the settings, open the System
> > control
> > panel, click the Advanced tab, click Performance settings button, click Data
> > Execution Prevention tab.  If you don't want Euphoria to crash, you should
> > either
> > have the first radio selected (turn on DEP for essential Windows programs
> > and
> > services only) or you will need to create an exception for your program if
> > the
> > second radio is selected (turn on DEP for all programs and services except
> > those
> > I select).
> > 
> > I recently ran into this issue again and it was nearly impossible to debug.
> > 
> > -- Brian
> 
> Disabling DEP is not a good idea, your app should run with it on. DEP is
> used to prevent viruses from running malicious code from memory locations,
> and almost every XP computer with Service Pack 2 installed will have this
> enabled by default. You cannot tell every user who wants to run your
> app to disable DEP.
> 
> 
> ----If you continue to do what you have always done,
> you will get what you have always gotten.----

I'm not sure if my last message was submitted or was closed via accidental
keystroke so forgive me if I sound redundant.

I searched the list and found that I mentioned that Windows *software* DEP does
not affect Euphoria Windows programs.  However, my latest job requires that I
develop running on x64 systems running W2k3 Server.  My last dev box must have
had hardware DEP enabled because I had to disable it to get Eu windows programs
working.

If your user has processor-level DEP capabilities, it *might* cause a
machine-level exception if these *strong* settings are enabled.

-- Brian