Is there a way to programmatically tell if particular block of memory was not freed by FastMM?

Question

I am trying to detect if a block of memory was not freed. Of course, the manager tells me that by dialog box or log file, but what if I would like to store results in a database? For example I would like to have in a database table a names of routines which allocated given blocks.

After reading a documentation of FastMM I know that since version 4.98 we have a possibility to be notified by manager about memory allocations, frees and reallocations as they occur. For example OnDebugFreeMemFinish event is passing to us a PFullDebugBlockHeader which contains useful informations. There is one thing that PFullDebugBlockHeader is missing - the information if the given block was freed by the application.

Unless OnDebugFreeMemFinish is called only for not freed blocks? This is which I do not know and would like to find out.

The problem is that even hooking into OnDebugFreeMemFinish event I was unable to find out if the block was freed or not.

Here is an example:

program MemLeakTest;

{$APPTYPE CONSOLE}

uses
  FastMM4, ExceptionLog, SysUtils;


procedure MemFreeEvent(APHeaderFreedBlock: PFullDebugBlockHeader; AResult: Integer);
begin
//This is executed at the end, but how should I know that this block should be freed
//by application? Unless this is executed ONLY for not freed blocks.
end;

procedure Leak;
var
  MyObject: TObject;
begin
  MyObject := TObject.Create;
end;

begin
  OnDebugFreeMemFinish := MemFreeEvent;
  Leak;
end.

What I am missing is the callback like:

procedure OnMemoryLeak(APointer: PFullDebugBlockHeader);

After browsing the source of FastMM I saw that there is a procedure:

procedure LogMemoryLeakOrAllocatedBlock(APointer: PFullDebugBlockHeader; IsALeak: Boolean);

which could be overriden, but maybe there is an easier way?

Answer 1

Even if such handler exist, it would be nearly useless, as everything, including DB would be shut down at the time when FastMM reports leaks.

So, I suggest you to turn on LogErrorsToFile along with FullDebugMode conditionals in FastMM4Options.inc. This will give you a text file with leaks, which later you can parse and put into DB.