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

Rohit Gupta rohit at cfl.co.nz
Thu Apr 5 10:59:05 NZST 2007


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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>>>>>>>
>>>>>>
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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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