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

Report #: 100163

Status: Closed

TThread.Start dont work for me

Project: Delphi

Build #: 16.0.4276.44006

Version: 16.1

Submitted By: Dmitry Aleshin

Report Type: Basic functionality failure

Date Reported: 10/17/2011 1:41:27 PM

Severity: Infrequently encountered problem

Last Updated: 10/19/2011 1:17:40 AM

Platform: All versions

Internal Tracking #:

Resolution: Test Case Error (Resolution Comments)

Resolved in Build: : None

Duplicate of: None

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Description

I've noticed that resume method is deprecated. But start method is not works for me

Steps to Reproduce:

Create a descendant fo TThread. Override contructor.

constructor TThreadDescendant.Create();
begin
inherited Create(True);
Start;
end;

this code raise an exception for me.

Workarounds

None

Attachment

Project1.zip

Comments

Tomohiro Takahashi at 10/18/2011 5:28:44 AM -

Could you please attach sample project to reproduce/verify your issue?

Dmitry Aleshin at 10/18/2011 8:02:35 PM -

I've attached it

Tomohiro Takahashi at 10/19/2011 1:32:49 AM -

>[Steps]
> ...
> this code raise an exception for me.
Do you get EThread excetion, right?
You will be able to find the reason of the error in System.Classes.pas.
----------
  TThread = class
  private type
    ...
    // Use Start after creating a suspended thread.
    procedure Start;
    ...
    ...
procedure TThread.InternalStart(Force: Boolean);
begin
...
    if ResumeThread(FHandle) <> 1 then
      raise EThread.Create(SThreadStartError);
...
----------

>   // Use Start after creating a suspended thread.
Generally speaking, inside constructor, we should not call a method(in this case, Start method), which is commonly called by outside.
So, correct code is below. Please call Start method after finishing construction of TThread completely.
-----------
...
  TThreadDescendant = class(TThread)
  protected
    procedure Execute; override;
  public
    constructor Create;
  end;
...
constructor TThreadDescendant.Create();
begin
  inherited Create(True);
  //Start;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  t: TThreadDescendant;
begin
  t := TThreadDescendant.Create;
  t.Start;
end;

procedure TThreadDescendant.Execute;
begin
end;
-----------

Dmitry Aleshin at 10/23/2011 8:16:19 PM -

I dont have sources in starter. So i cannot understand the reason of exception.

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