-----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
