[Lazarus] Is it possible to find the location of an EAccessViolation, with Lazarus?

[Carlos E. R.]

Hi,

a program of mine crashed with:

Exception at 0000000000401B4A: EAccessViolation:
Access violation.


Is it possible to find the location line of that address?


Very long ago, with turbopascal, it was possible to type the address of the fault in a box in the compiler, which would build again the source and stop at the exact location. I do not see similar thing in Lazarus. Did I miss it?



I know where it happened, more or less, from the messages on screen and syslog.
Maybe someone here can see the problem in the code.


procedure TMyApplication.DoRebootRouter;
 {See <http://wiki.freepascal.or/Executing_External_Programs#TProcess> 
  for the doc on calling a program and getting its output.}
   const
     BUF_SIZE = 2048; // Buffer size for reading the output in chunks
   var
     AProcess     : TProcess;
     OutputStream : TStream;
     BytesRead    : longint;
     Buffer       : array[1..BUF_SIZE] of byte;
     ExitCode,
     ExitStatus   : Integer;
begin
   LastRouterRebootTimestamp:= Now;
   inc(RebootTimes);
   ExitCode := -1;
   AProcess := TProcess.Create(nil);
   try
      AProcess.Executable := '/usr/local/bin/egctl';
      AProcess.Parameters.Add('Regleta');
      AProcess.Parameters.Add('off');
      AProcess.Parameters.Add('off');
      AProcess.Parameters.Add('off');
      AProcess.Parameters.Add('off');

      AProcess.Execute;                          <==== this does execute.
      OutputStream := TMemoryStream.Create;
      repeat
         BytesRead := AProcess.Output.Read(Buffer, BUF_SIZE);
         OutputStream.Write(Buffer, BytesRead)
      until BytesRead = 0;
      ExitCode:= AProcess.ExitStatus;
      ExitStatus:= AProcess.ExitStatus
   finally
      AProcess.Free;
   end;

   syslog(log_info, 'Called %s, got EC: %d ED: %d'#10, ['egctl', ExitCode, ExitStatus]);   <====  this part doesn't execute.
   Writeln('Got exitcode ', AProcess.ExitCode, ' ExitStatus: ', AProcess.ExitStatus);



The external program runs fine.

The screen output was:

Last sucessfull ping was more than 60 seconds ago, rebooting the router.
Exception at 0000000000401B4A: EAccessViolation:
Access violation.
socket 1 - off		<=== child program
socket 2 - off
socket 3 - off
socket 4 - off


Syslog entries are these:

<16.6> 2018-05-12T07:25:18.455969+02:00 Isengard WatchDog - - -  WatchDog MARK! Status: Router 1 (F/T 0/48) Google 1 (F/T 0/8) Rebooting 0  Reboots 0
<16.6> 2018-05-12T07:47:20.514116+02:00 Isengard WatchDog - - -  Last sucessfull ping was more than 60 seconds ago, rebooting the router.
<16.6> 2018-05-12T07:47:20.515184+02:00 Isengard WatchDog - - -  Ending

The second line indicates that the procedure shown above is called.

The third line comes from here:


destructor TMyApplication.Destroy;
begin
   ping.Free;
   syslog(log_info,'Ending',[1234]);
   closelog;
   inherited Destroy;
end;   



Ideas?


-- 
Cheers / Saludos,

		Carlos E. R.
		(from 42.3 x86_64 "Malachite" at Telcontar)

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