Open Source Messenger for Any Version of Windows

Environment: VC6, WIN XP SP1

While I was writing a LAN (Local Area Network) chat program, I noticed that many people on my LAN use different programs for message sending and that not all of them are compatible with other programs. The second problem I noticed was that many of them don't work on Win95/98. So, I decided to add this functionality to my program. I started to search for a universal method for all Windows versions and most message-sending programs and I discovered that the best solution is to add a MAILSLOT mechanism to my program (along with some others). The first place I searched was MSDN and CodeGuru, but I didn't find any complete solution. That's the main reason I wrote this article.

I wrote a function that writes to the mailslot (I saw how to do that on CodeGuru) and a simple class that reads from the mailslot (I found many explanations and put all of them together—mostly from "PJ Naughter"). I also wrote a simple project so you can see how to link these two things and put everything in the right places.

Here are the steps you need to do:

  1. Add "mailslot.h" and "mailslot.cpp" to your project.
  2. Create a CMailSlot instance in your main class (for example, m_serverMailSlot).
  3. Add an OnTimer event to your project and somewhere set the Timer. For example, you can do that in OnInitDialog():
    SetTimer(timerID, 2000, NULL);    //this is for 2 seconds
  4. Create a CheckForNewMessage() function. That is the place where you will be calling an m_serverMailSlot.Read() function.
  5. In the OnTimer() function, call the CheckForNewMessage() function, which will check for new messages and display them (if there are any waiting).

That is all. I know that there are better ways to send messages, but this is the most-used method so you will be able to receive messages from many different programs and to use it on any Windows operating system.

If you have any questions or need some extra help with this, e-mail me... If there are any suggestions or comments, you are most welcome to contact me, too.

You can download "mailslot.h", "mailslot.cpp" (contains CServerMailslot), and "sendfun.txt". You can also download the sample project and executable file.

Downloads

Download executable - 72 Kb
Download demo project - 32 Kb
Download source - 3 Kb


Comments

  • Nice! But one question...

    Posted by Legacy on 03/05/2003 12:00am

    Originally posted by: VaKa

    Your App nice and very helpfull for me in understanding mailslot messaging.
    
    

    But I noticed that if I send a message from one PC to another, second PC receives that message multiple times.
    (in described case one PC running Windows NT4, another - Windows 98)

    Can You help me in understanding that?

    Reply
Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Live Event Date: May 6, 2014 @ 1:00 p.m. ET / 10:00 a.m. PT While you likely have very good reasons for remaining on WinXP after end of support -- an estimated 20-30% of worldwide devices still are -- the bottom line is your security risk is now significant. In the absence of security patches, attackers will certainly turn their attention to this new opportunity. Join Lumension Vice President Paul Zimski in this one-hour webcast to discuss risk and, more importantly, 5 pragmatic risk mitigation techniques …

  • When it comes to desktops – physical or virtual – it's all about the applications. Cloud-hosted virtual desktops are growing fast because you get local data center-class security and 24x7 access with the complete personalization and flexibility of your own desktop. Organizations make five common mistakes when it comes to planning and implementing their application management strategy. This eBook tells you what they are and how to avoid them, and offers real-life case studies on customers who didn't let …

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds