rawlukn

First time I’ve seen it.  I use Windows XP while the client uses Windows 7; I wonder if 7 is more unforgiving of “reading someone else’s memory”?

(So far) I have only seen the error on a Windows XP machine with a built exe. I haven't programmed in C for a while now but I seem to recall having received errors when accessing memory that was not allocated to my application. I cannot recall if both read/writes did it or only writes. However, I can believe that these days windows would watch to make sure an application is only using the memory allocated to it (reading or writing).

Did your customer find a reproducible way to cause the error?

drjdpowell

I just noticed an issue with my code (see image attached) that could be related. I forgot to use a shift register to keep track of the "SQLite Connection" which keeps track of the db handle. Glancing at your code this could be a problem if the db handle changes in a 'Prepare Statement' but then isn't used on the next iteration of my loop.

Is it possible that the db handle could change during a singe SQLite session? From a quick read on the sqlite website it doesn't appear to be the case. If it did change I could believe this might trickle down to errors later, but I'd assume the error would original at the library call in 'SQLite Prepare' and not the pointer to C string.

Hello,

 

I'm using your library and it works fine the most time.

 

I do all SQLite Operation sequentially and not in parallel. But sometimes I get this error:

Fehler 1097 bei Knoten zum Aufruf externer Bibliotheken in SQLite.lvlib:Pointer-to-C-String to String.vi->SQLite.lvlib:Connection.lvclass:Prepare.vi:1->SQLite.lvlib:Connection.lvclass:Execute SQL.vi->db_log_data.vi->_Main.viSQL: "SELECT id FROM log_data ORDER BY id ASC LIMIT 1" Mögliche Ursachen: LabVIEW: Es trat ein Ausnahmefehler im externen Code auf, der vom Knoten "Aufruf externer Bibliotheken" aufgerufen wurde. Diese Ausnahme könnte Fehler im Speicher von LabVIEW verursacht haben. Speichern Sie alle Projekte an einem neuen Ort und starten Sie LabVIEW erneut.

This error occures not always within the same VI. Sometimes the error occures within a DELETE query, sometime within a SELECT query.

The VI works for example 1000 times and then the error occures. After restarting my program it works 700 times and the the error occures.

 

Maybe is a synchonisation problem, but I don't think so, because I only use "Execute SQL" sequentially.

 

Do you have any idea what could cause such an error?

 

Regards

Matze

I am receiving the same error on the odd occasion using this library. So far it has only occurred when running a built EXE and not when running from source. I have yet to figure out a reproducible way to trigger it:

Error 1097 occurred at Call Library Function Node in SQLite.lvlib:Pointer-to-C-String to String.vi->SQLite.lvlib:Connection.lvclass:Prepare.vi->Save data to row.vi->Save test entry to Database.vi->Tests Window GUI.vi->PGAT Main.vi SQL: "UPDATE measurements SET "MUX HV Positive [V]"=? WHERE ROWID=36" Possible reason(s): LabVIEW:  An exception occurred within the external code called by a Call Library Function Node. The exception might have corrupted the LabVIEW memory. Save any work to a new location and restart LabVIEW.

Are you receiving it when running from source, compiled, or both?

drjdpowell:

If I manage to figure out how to trigger the problem reliably I will probe the pointer and post. Unfortunately, there is a chance this is only a problem for my compiled EXE.

Many thanks for putting this library out to the public. It has been very useful to me so far.