Solved

Thread in Delphi - time-problem

Posted on 2013-11-26
6
540 Views
Last Modified: 2013-11-26
Hi

In an application I comunicate with a mobile device. If the device is not in the dockingstation it is possible, that calling a function will respond after a timeout of i.e. 60 seconds. So my idea was to program this in a thread.
  TPdaSyncThread = class(TThread)
  private
    procedure doProcess;
  protected
    procedure Execute; override;
  public
    constructor Create(... myParams);
  end;

constructor TPdaSyncThread.Create(... myParams);
begin
  FreeOnTerminate := True;
  inherited Create(False);
  ....
end;

procedure TPdaSyncThread.doProcess;
begin
  Sleep(30000);  //just to "simulate" calling the function that will return after a timeout
end;

procedure TPdaSyncThread.Execute;
begin
  while not Terminated do
  begin
    Synchronize(self,doProcess);
  end;
end;

Open in new window

In the main-thread I have a procedure "AppMessage" (Application.Onmessage := "AppMessage". During the 30 seconds (sleep) this procedure is never called. I think I didn't understand something with threading??
0
Comment
Question by:formi
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
6 Comments
 
LVL 37

Expert Comment

by:Geert Gruwez
ID: 39677938
what is the rest of your code ?

the only thing this thread does is sleep ... every 30 seconds
0
 
LVL 37

Accepted Solution

by:
Geert Gruwez earned 250 total points
ID: 39677944
procedure TPdaSyncThread.doProcess;
begin
  // ... call your AppMessage here
end;

procedure TPdaSyncThread.Execute;
begin
  while not Terminated do
  begin
    Sleep(30000);
    Synchronize(self,doProcess);
  end;
end;
0
 
LVL 19

Assisted Solution

by:MerijnB
MerijnB earned 250 total points
ID: 39677973
Why do you call Synchronize? that will make the sleep happen in main thread, exactly what you don't want?
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 

Author Comment

by:formi
ID: 39677993
Yes you are right. it only sleeps - as I wrote in the code's comment to simulate the long answer-time of a routine. But I think you gave me the tip: is it correct that during calling a routine with "Synchronize" no other thread gets time to execute? If "Yes" I have to call the time-consuming routines in the execute-loop and not in the synchronize-routine.
0
 

Author Closing Comment

by:formi
ID: 39678004
Thanks you helped me both!
0
 
LVL 37

Expert Comment

by:Geert Gruwez
ID: 39679967
make sure all procedures in synchronize are short
and don't update/draw anything on other forms from inside a thread

you'll have circular unit reference to start with
the code may be simple but it will difficult to follow the flow of just 1 unit
0

Featured Post

[Webinar] Code, Load, and Grow

Managing multiple websites, servers, applications, and security on a daily basis? Join us for a webinar on May 25th to learn how to simplify administration and management of virtual hosts for IT admins, create a secure environment, and deploy code more effectively and frequently.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
delphi parse string to params 3 181
Reconfigure Delphi Install? 2 78
control image tags in a string ? 12 171
FMX TEdit KeyUp handler detecting  "enter" key 4 64
This article explains how to create forms/units independent of other forms/units object names in a delphi project. Have you ever created a form for user input in a Delphi project and then had the need to have that same form in a other Delphi proj…
Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
In a recent question (https://www.experts-exchange.com/questions/29004105/Run-AutoHotkey-script-directly-from-Notepad.html) here at Experts Exchange, a member asked how to run an AutoHotkey script (.AHK) directly from Notepad++ (aka NPP). This video…
Are you ready to implement Active Directory best practices without reading 300+ pages? You're in luck. In this webinar hosted by Skyport Systems, you gain insight into Microsoft's latest comprehensive guide, with tips on the best and easiest way…

752 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question