Lately I'm getting a bunch of those. I thought it was because I was using an old version of lazarus, but now I upgraded to 0.9.30 (self compiled from http:://svn.freepascal.org/svn/lazarus/tags_lazarus_0_9_30 with fpc 2.4.2 under win32) and I got another strange one.

The exception, according to the stack trace, is in line 27 of monitor.inc:

function TMonitor.GetInfo(out Info: TMonitorInfo): Boolean;
begin
   Info.cbSize := SizeOf(TMonitorInfo);
   Result := GetMonitorInfo(Handle, @Info); <<--here
end;

Called from here:

function TMonitor.GetBoundsRect: TRect;
var
   Info: TMonitorInfo;
begin
   if GetInfo(Info) then <<--here
     Result := Info.rcMonitor
   else
     Result := Rect(0, 0, 0, 0);
end;

So I don't understand how an access violation is possible (unless windows doesn't look at the cbSize field and tries to access past its size). I suspect that the PC where the program is running has some problem (maybe a virus?), since I got another access violation on the same PC (actually I don't know, I didn't manage to get a stack trace, the main form just "vanished" after pressing a button, a different one than this time, and that prompted me to upgrade lazarus) but I'm worried.

Of course it isn't reproducible (it happened only once, inside a TOpendialog.Execute, I tried many many times after the access violation with no problem).

Any idea?

Bye

?
?

Luca Olivetti hat am 4. Mai 2011 um 13:44 geschrieben:

Maybe a heap/stack corruption. Compile with many checks: -ghtl -Criot -Sa The problem is probably in some package you installed.

Mattias
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Al 04/05/11 17:36, En/na Mattias Gaertner ha escrit:

Could be and I'll try that, however it's the same set of packages I've been using for some years without hitting this problem.

Bye

Some bugs can get very old before becoming apparent. Sometimes a bugfix in some other place can do this.

Many lazarus devels test with above checks, but only their set of packages.

Mattias

Al 04/05/11 19:24, En/na Mattias Gaertner ha escrit:

Many lazarus devels test with above checks, but only their set of packages.

It's enough to set those options in my project or do I have to set them in every package?
I tried adding those options in
Project->Project options->Compiler options->Other-Custom options

and it didn't rebuild the packages, so I suppose I'll have to set them in every package (or in fpc.cfg and rebuild everything?)

Bye

Yes, every package has its own set of options, so you know you are using the same options as the developer of the package. You could add a macro.
For example many packages contain the macro $(IDEBuildOptions) in their custom options. This macro are the options of the Lazarus build dialog.

Mattias

Al 04/05/2011 17:36, En/na Mattias Gaertner ha escrit:

Luca Olivetti hat am 4. Mai 2011 um 13:44 geschrieben:

...

Well, I tried with all packages (except the LCL and FCL)) as well with my application compiled with those options, and while I found a couple of (intentional) range exceptions, I could find nothing else :-(

Bye