[fpc-devel] Need patch for bugs : 0011503 / 0009472

[Vincent Snijders]

Michael Van Canneyt schreef:
> 
> On Thu, 19 Jun 2008, Boian Mitov wrote:
> 
>> Here is a code sniped that sows just one example of the problem:
>>
>> This is a very simple example of how important the order really is:
>> We have even more crucial problems related with this. This is just a simple
>> one:
>>
>> destructor  TALBasicAudioOut.Destroy();
>> var
>>  WriteLock : IOWLockSection;
>>
>> begin
>>  WriteLock := FLock.StopLock();
>>
>>  FInputPin.Free();
>>  FEnablePin.Free();
>>  FMasterPumping.Free();
>>  WriteLock := NIL;
>>  FLock.Free();
>>  inherited;
>> end;
>>
>> You can see that the WriteLock  MUST be released before the   FLock.Free();,
> 
> Maybe Jonas or Florian can comment on this.

When you said function blocks, it made me think of nested procedures.

So I think you write it like:

destructor  TALBasicAudioOut.Destroy();
  procedure DoWriteProtectedThings;
  var
    WriteLock : IOWLockSection;

  begin
  WriteLock := FLock.StopLock();

  FInputPin.Free();
  FEnablePin.Free();
  FMasterPumping.Free();
  end;

begin
  DoWriteProtectedThings;
  FLock.Free();
  inherited;
end;

Then you have made it clear that after WriteLock has to be cleared 
before freeing the lock. Of course it still fails if a periodic mark and 
sweep would be used by the compiler.

Vincent