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Report From: Delphi-BCB/RTL/Delphi/Thread support [ Add a report in this area ]

Report #: 90487

Status: Closed

TMonitor.Enter, closing app, hangs in SysUtils.DoneMonitorSupport

Project: Delphi

Build #: 14.0.3593.25826

Version: 14.0

Submitted By: andre mussche

Report Type: Basic functionality failure

Date Reported: 12/22/2010 11:57:17 PM

Severity: Serious / Highly visible problem

Last Updated: 3/20/2012 2:24:39 AM

Platform: All platforms

Internal Tracking #: 281510

Resolution: Test Case Error (Resolution Comments)

Resolved in Build: : 16.0.4223.41907

Duplicate of: None

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Description

When using TMonitor.Enter in 2 threads (so one gets locked) and never releasing the lock, the application will hang (100%) in DoneMonitorSupport when closing.

Steps to Reproduce:

1: Use code below
2: start app
3: close app
4: 100 cpu%!

==============================

unit Unit5;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  TForm5 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

  TTestThread = class(TThread)
  protected
    procedure Execute;override;
  end;

var
  Form5: TForm5;

implementation

{$R *.dfm}

var
  o: TObject;

procedure TForm5.FormCreate(Sender: TObject);
begin
  o := TObject.Create;
  System.TMonitor.Enter(o);

  TTestThread.Create(False {direct run});
end;

{ TTestThread }

procedure TTestThread.Execute;
begin
  System.TMonitor.Enter(o);
end;

end.

Workarounds

None, only be very sure to release all locks and free all objects...

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