Mysterious user breakpoint? 
Author Message
 Mysterious user breakpoint?

Hello everyone,
I'm trying to debugg my app by "running to cursor"...but
everytime the app starts it immediately stops with a
messagebox saying "User breakpoint called from code
Ox77f7f570" and then it goes into debug mode and displays
what appears to be a bunch of assembly code.  This happens
before it gets to the cursor.  I haven't set any
breakpoints, I'm just trying to run to cursor.  What the
heck is happening and how can I fix this? Thanks in
advance everyone!

-Lionel



Sat, 16 Jul 2005 23:21:59 GMT  
 Mysterious user breakpoint?
Look in the output window (which should always be open in
my opinion). You will probably see some messages from the
operating system telling you that you have some memory
errors.

In recent versions of Windows if you are running under a de{*filter*}
the heap manager checks for certain memory errors - free twice,
modify after free, memory overwrites, etc. - and triggers a
user breakpoints if one of these events occurs.

So, look in the output window to see what the problem is, then
look in the call stack to see where it was detected, then fix the
problem. Third party tools like BoundsChecker may be useful
if you can't isolate the problem.

These memory errors are very serious, which is why a breakpoint
is triggered.

--
This posting is provided "AS IS" with no warranties, and confers no rights.


Quote:
> Hello everyone,
> I'm trying to debugg my app by "running to cursor"...but
> everytime the app starts it immediately stops with a
> messagebox saying "User breakpoint called from code
> Ox77f7f570" and then it goes into debug mode and displays
> what appears to be a bunch of assembly code.  This happens
> before it gets to the cursor.  I haven't set any
> breakpoints, I'm just trying to run to cursor.  What the
> heck is happening and how can I fix this? Thanks in
> advance everyone!

> -Lionel



Sun, 17 Jul 2005 02:48:57 GMT  
 Mysterious user breakpoint?
The moment the de{*filter*} launches the app, it displays the
breakpoint window saying that a user breakpoint has been
encountered.  It never used to do this under debugging,
and the code that I've modified that may have caused a
problem hasn't been executed yet since I can't even
interact with the app before it throws up this window.  I
don't believe the problem is as you have stated above, but
I will take your advice and take a look in the output
window (and thank you for replying).

Quote:
>-----Original Message-----
>Look in the output window (which should always be open in
>my opinion). You will probably see some messages from the
>operating system telling you that you have some memory
>errors.

>In recent versions of Windows if you are running under a
de{*filter*}
>the heap manager checks for certain memory errors - free
twice,
>modify after free, memory overwrites, etc. - and triggers
a
>user breakpoints if one of these events occurs.

>So, look in the output window to see what the problem is,
then
>look in the call stack to see where it was detected, then
fix the
>problem. Third party tools like BoundsChecker may be
useful
>if you can't isolate the problem.

>These memory errors are very serious, which is why a
breakpoint
>is triggered.

>--
>This posting is provided "AS IS" with no warranties, and
confers no rights.



>> Hello everyone,
>> I'm trying to debugg my app by "running to cursor"...but
>> everytime the app starts it immediately stops with a
>> messagebox saying "User breakpoint called from code
>> Ox77f7f570" and then it goes into debug mode and
displays
>> what appears to be a bunch of assembly code.  This
happens
>> before it gets to the cursor.  I haven't set any
>> breakpoints, I'm just trying to run to cursor.  What the
>> heck is happening and how can I fix this? Thanks in
>> advance everyone!

>> -Lionel

>.



Sun, 17 Jul 2005 04:18:49 GMT  
 Mysterious user breakpoint?
The reason you only see a bunch of assembly code is
because you don't have OS debug symbols installed.

Install the symbols, reproduce the error and look at the
call stack. It will make much more sense this time.

Quote:

> Hello everyone,
> I'm trying to debugg my app by "running to cursor"...but
> everytime the app starts it immediately stops with a
> messagebox saying "User breakpoint called from code
> Ox77f7f570" and then it goes into debug mode and displays
> what appears to be a bunch of assembly code.  This happens
> before it gets to the cursor.  I haven't set any
> breakpoints, I'm just trying to run to cursor.  What the
> heck is happening and how can I fix this? Thanks in
> advance everyone!

> -Lionel



Sun, 17 Jul 2005 07:18:44 GMT  
 Mysterious user breakpoint?

You might wonder where the "user breakpoint called..."
message comes from. It's actually a debug aid, the debug
heap manager will help to see you're not freeing memory
twice etc. Also, any variable allocated on the stack but
not initialized will be filled with 0xCC, which is the
value of a breakpoint instruction. So if you happen to
execute code on the stack you might run into a breakpoint
instruction.

As Pavel wrote, make sure you install OS symbols, that helps
a lot while debugging.

A really useful bug to learn debugging is "Debugging Applications"
by John Robbins.

http://www.*-*-*.com/
http://www.*-*-*.com/
http://www.*-*-*.com/
http://www.*-*-*.com/


Quote:
> The moment the de{*filter*} launches the app, it displays the
> breakpoint window saying that a user breakpoint has been
> encountered.  It never used to do this under debugging,
> and the code that I've modified that may have caused a
> problem hasn't been executed yet since I can't even
> interact with the app before it throws up this window.  I
> don't believe the problem is as you have stated above, but
> I will take your advice and take a look in the output
> window (and thank you for replying).

> >-----Original Message-----
> >Look in the output window (which should always be open in
> >my opinion). You will probably see some messages from the
> >operating system telling you that you have some memory
> >errors.

> >In recent versions of Windows if you are running under a
> de{*filter*}
> >the heap manager checks for certain memory errors - free
> twice,
> >modify after free, memory overwrites, etc. - and triggers
> a
> >user breakpoints if one of these events occurs.

> >So, look in the output window to see what the problem is,
> then
> >look in the call stack to see where it was detected, then
> fix the
> >problem. Third party tools like BoundsChecker may be
> useful
> >if you can't isolate the problem.

> >These memory errors are very serious, which is why a
> breakpoint
> >is triggered.

> >--
> >This posting is provided "AS IS" with no warranties, and
> confers no rights.



> >> Hello everyone,
> >> I'm trying to debugg my app by "running to cursor"...but
> >> everytime the app starts it immediately stops with a
> >> messagebox saying "User breakpoint called from code
> >> Ox77f7f570" and then it goes into debug mode and
> displays
> >> what appears to be a bunch of assembly code.  This
> happens
> >> before it gets to the cursor.  I haven't set any
> >> breakpoints, I'm just trying to run to cursor.  What the
> >> heck is happening and how can I fix this? Thanks in
> >> advance everyone!

> >> -Lionel

> >.



Mon, 18 Jul 2005 04:21:24 GMT  
 
 [ 5 post ] 

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