You
will not find an exact match of the address.
So
look for the method that has a starting address just less than $691a42 eg
something like $691000 (depends on the size of the method).
If no
methods have addresses of around this value, then the program was re-located on
the machine, and then the only way to find the correct address is from a dr
watson dump or one of the exception trappers.
Myles
-----Original
Message-----
From: Mark Howard [mailto:[EMAIL PROTECTED]
Sent: Tuesday, 2 December 2003 17:14
To: Myles Penlington
Subject: RE: [DUG] Making use of AV error messages
From: Mark Howard [mailto:[EMAIL PROTECTED]
Sent: Tuesday, 2 December 2003 17:14
To: Myles Penlington
Subject: RE: [DUG] Making use of AV error messages
OKOne thing at a time..I have created a .MAP file and searched it for both of the references in the error message(ie 00691A42 and 000002F8) and it comes up blank.Was this the idea?MarkOn 2 Dec 2003 at 16:27, Myles Penlington wrote:>>> -----Original Message-----> From: Mark Howard [mailto:[EMAIL PROTECTED]> Sent: Tuesday, 2 December 2003 16:08> To: Myles Penlington> Subject: RE: [DUG] Making use of AV error messages>>> Thanks Myles>> On 2 Dec 2003 at 15:45, Myles Penlington wrote:>> > >From this I can say two things.> > 1. It is a nil pointer reference - 2F8 is the offset - so it is> > quite a large object/array/record (Offset760).> What is the significance of this?> Because the offset is quite large it will limit your search in terms> of objects that could have caused the error. Most objects are less> than 200 bytes in size.>> 2. Create a map file for the> > executable. From this you can find the actual method where the AV> > happened.> OK. Er . . . How do I do this please?> Project linker options - check the detailed map box. The alternative> is to run your program and then stop/pause it and use search/find> error and key in the address $06 ... ie compile to displacement. > > I> suspect from the address given, that the application has not been >> loaded at a different base address. What is the significance of this,> too.? Just helps in debugging, if the AV was mentioned at say> $1023304, and knowing your program is not 64Meg in size, tells you it> was loaded at a different address, so the address then given in the AV> message is no good - unless you have a dump from Dr Watson that gives> the load address, then you can calculate the offset in the code when> running on your machine of the actual AV/Code address.>> Knowing the actual method may not> > help, you may need a stack trace instead. So as mentioned last week> > get one of the good AV trappers that will output you a stack trace> > eg www.madshi.net> Am I going to be able to get to the bottom of this doing these things> on my development machine, which is not generating these errors?>> >> Probably not. But you should be able to find the line where the> >> error is> happening, and knowing that a object variable is nil is a great help -> it limits the kind of code to look at. eg this is probably a property> reference, using a nil object value. From there you can work backwards> to see the possible causes.>> One other thing - Delphi has issues with printers if the default> printer is on a network and the network cable is not plugged in - so> this may be a good candidate on a portable computer. If the code is> anywhere near the printers unit, then you need to fix the code in> here.>> >> > Myles.> >> >> > -----Original Message-----> > From: Mark Howard [mailto:[EMAIL PROTECTED]> > Sent: Tuesday, 2 December 2003 15:32> > To: [EMAIL PROTECTED]> > Subject: [DUG] Making use of AV error messages> >> >> > Hi> >> > I have a site where my app is installed on a Server along with it's> > database. Various workstations have short cuts defined that point> > to this single instance of the app on the server.> >> > The app is running fine on several desktop PC's. They have recently> > tried to run it from a Laptop and get an (AV) error message as it> > starts up, and after that it runs wonkily, throwing other errors.> > (The first Laptop they tried was XP - then they tried a second that> > was running Win2K Pro and was in all other respects a virgin ie no> > Norton or anything).> >> > The first message is> > "Access violation at address 00691A42 in Module 'PSLog.exe' Read of> > address 000002F8 "> >> > I would like to use this message to try to home in on what might be> > causing the errors - but have never (ever) done any debugging at> > this level.> >> > Is it possible that I could be "talked through" whatever is> > necessary, or is that to big an ask? It would need to be a a very> > basic level.> >> > Mark> > _______________________________________________> > Delphi mailing list> > [EMAIL PROTECTED]> > http://ns3.123.co.nz/mailman/listinfo/delphi> > _______________________________________________> > Delphi mailing list> > [EMAIL PROTECTED]> > http://ns3.123.co.nz/mailman/listinfo/delphi> >>> _______________________________________________> Delphi mailing list> [EMAIL PROTECTED]> http://ns3.123.co.nz/mailman/listinfo/delphi>--Forest Production Systems LtdCreators of PSLog Harvesting Information SystemWeb: www.pslog.co.nz
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