[DUG] Anyone got Crystal 11 to test major bug in CR

Neven MacEwan neven at mwk.co.nz
Thu Apr 5 11:04:01 NZST 2007


Rohit

I've got X1 release 2

N
> Has anyone got CR11 installed who is willing to try an very tiny app 
> to prove that CR is stuffed ?
>
> Neven MacEwan wrote:
>> Rohit Gupta wrote:
>>
>> "Hey Robert Zimmerman got a song for you, bout a young man called 
>> Dylan with a voice like sand and glue"
>>
>> Glad you found it (if you had)
>>
>> N
>>> Are you talking about John B Murphy or Frank Zimmerman ?
>>>
>>> I think I have found the problem.  It uses two callbacks from the 
>>> crpe.ddl back to TCrpe component (to local nested procedures in each 
>>> case).
>>> What amazes me is that works at all.  It also explains why the app 
>>> dies even when it is idle and finished doing the report many seconds 
>>> ago.  It is fiddling with data on the heap thats long gone.. and 
>>> what about the stack frame ?  Yeach !!
>>>
>>> We have just tried V11.  Luckiliy the VCL changes are minor and the 
>>> reports are working.  Still have to look at its source and test the 
>>> crash cases.
>>>
>>> Neven MacEwan wrote:
>>>> Rohit
>>>>
>>>> I think the crpe.dll was only written to be used by one app 
>>>> crpe.exe and is very sequence fragile,
>>>> I know the guy that wrote the VCL for it had all sorts of problems, 
>>>> I'd make sure you don't try to get it to do to many
>>>> things at the same time on the same instance
>>>>
>>>> HTH
>>>>
>>>> Neven
>>>>
>>>>> Robert,
>>>>>
>>>>> all this can not be correct.  How can a DLL be written that will 
>>>>> not work with more than one app at a time ?  Especially when there 
>>>>> are no common resources or files to use.  The data space is mapped 
>>>>> to the app that is using the dll.
>>>>>
>>>>> I have also discovered that the memory gets trashed asynchronously 
>>>>> of report access.  You can leave the app there and 10-30 seconds 
>>>>> later it will suddenly complain with rubbish errors or just 
>>>>> disappear.  This is when no one has even touched the keyboard in 
>>>>> that time.
>>>>>
>>>>>
>>>>> Robert martin wrote:
>>>>>> Hi
>>>>>>
>>>>>> Yes.  But what bugs will they have introduced in the process?
>>>>>>
>>>>>> Don't know if two would work.  I would guess yes.
>>>>>>
>>>>>> Rob Martin
>>>>>> Software Engineer
>>>>>>
>>>>>> phone +64 03 377 0495
>>>>>> fax   +64 03 377 0496
>>>>>> web www.chreos.com
>>>>>>
>>>>>> Wild Software Ltd
>>>>>>
>>>>>>
>>>>>>
>>>>>> Rohit Gupta wrote:
>>>>>>> I see that BO are saying the the crpe is now threadsafe in v11.  
>>>>>>> Do I believe them ?
>>>>>>>
>>>>>>> Question - do you know if it two crpe components  are allowed in 
>>>>>>> the same app ?  We use one to interrogate the report for 
>>>>>>> formulas etc and the other is bound to a form for running the 
>>>>>>> report.
>>>>>>>
>>>>>>> Robert martin wrote:
>>>>>>>> Hi Rohit
>>>>>>>>
>>>>>>>> It has been some time since I used the Crpe method of accessing 
>>>>>>>> Crystal but my understanding is it is not Thread safe and 
>>>>>>>> therefore if you use it in threads or try running multiple 
>>>>>>>> copies of reports it can go bang.  This may be what you are 
>>>>>>>> experiencing.
>>>>>>>>
>>>>>>>> In the end w gave up on Crpe and now use the Com object to run 
>>>>>>>> them.  This works better but comes with other issues.  I think 
>>>>>>>> it is the better access method though.
>>>>>>>>
>>>>>>>> Not a log of help i'm afraid :)
>>>>>>>>
>>>>>>>> Rob Martin
>>>>>>>> Software Engineer
>>>>>>>>
>>>>>>>> phone +64 03 377 0495
>>>>>>>> fax   +64 03 377 0496
>>>>>>>> web www.chreos.com
>>>>>>>>
>>>>>>>> Wild Software Ltd
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Rohit Gupta wrote:
>>>>>>>>> In our real app, the program crashes randomly (regularly for 
>>>>>>>>> some users) at the instance that Crpe is used.  The app 
>>>>>>>>> basically disappears which implies that substantial code 
>>>>>>>>> and/or stack is corrupted.
>>>>>>>>>
>>>>>>>>> In a smaller app that only opens the report to get some stats 
>>>>>>>>> (it does not connect to the database), I can get it to crash 
>>>>>>>>> in the same fashion predictably.
>>>>>>>>>
>>>>>>>>> The sequence of events is open two copies of the app )or one 
>>>>>>>>> copy of the app and the CRW designer)
>>>>>>>>> Open any report in the first app (which always assignes 
>>>>>>>>> ReportName to blank and does not destroy the crpe component
>>>>>>>>> Open any report in the second app or CRW Designer
>>>>>>>>> Open any report in the first app and its gone with no trace.
>>>>>>>>>
>>>>>>>>> In real life the users can not run multiple copies, the app 
>>>>>>>>> takes care of that.  However the symptoms are identical 
>>>>>>>>> leading me to believe that if I can find the cause of the 
>>>>>>>>> second crash, I can fix the first one.
>>>>>>>>>
>>>>>>>>> Any clues anyone ?
>>>>>>>>> I cant find anything pertinent on google, except for one item 
>>>>>>>>> where the author insists that the problem is a secret com 
>>>>>>>>> object that crpe launches and if you wait for it to finish and 
>>>>>>>>> terminate then there are no crashes.  However, delays dont 
>>>>>>>>> have any effect on my test case.
>>>>>>>>>
>>>>>>>>> In the debugger, if I keep doing F7, everything keeps 
>>>>>>>>> working.  But as soon as I press F8 or F9, it gets an AV 
>>>>>>>>> because it starts executing in hyperspace.
>>>>>>>>>
>>>>>>>>> _______________________________________________
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>>>>>>
>>>>>
>>>>> -- 
>>>>> *Rohit Gupta*
>>>>> * B.E. Elec.   M.E.   Mem IEEE    Associate IEE*
>>>>> *Technical Manager*
>>>>> *Computer Fanatics Limited*
>>>>> ** *Tel*     +64 9 4892280
>>>>> *Fax*    +64 9 4892290
>>>>> *Email  *rohit at cfl.co.nz <mailto:rohit at cfl.co.nz>**
>>>>> *Web    *www.cfl.co.nz <http://www.cfl.co.nz/>
>>>>>  
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>>>>
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>>>>
>>>>
>>>
>>> -- 
>>> *Rohit Gupta*
>>> * B.E. Elec.   M.E.   Mem IEEE    Associate IEE*
>>> *Technical Manager*
>>> *Computer Fanatics Limited*
>>> ** *Tel*     +64 9 4892280
>>> *Fax*    +64 9 4892290
>>> *Email  *rohit at cfl.co.nz <mailto:rohit at cfl.co.nz>**
>>> *Web    *www.cfl.co.nz <http://www.cfl.co.nz/>
>>>  
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>>
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>>
>>
>
> -- 
> *Rohit Gupta*
> * B.E. Elec.   M.E.   Mem IEEE    Associate IEE*
> *Technical Manager*
> *Computer Fanatics Limited*
> ** 
> *Tel*     +64 9 4892280
> *Fax*    +64 9 4892290
> *Email  *rohit at cfl.co.nz <mailto:rohit at cfl.co.nz>**
> *Web    *www.cfl.co.nz <http://www.cfl.co.nz/>
>  
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