Send – Messenger Service Pair

Environment: Windows NT 4 SP3, Visual C++ 6

The "Send"-"Messenger" pair are ment to replace the old "Net
send"-"Messenger". Actually I decided to try this because I was getting
annoyed with the same message boxes on the screen, and since I couldn’t find any
information about the old stuff, I made a new pair. The "send" part does very
little.It’s a Win32 console app that connects to a named pipe and writes to it. The
service is also a Win32 console app (Microsoft advices, isn’t it) that creates a icon in
the TrayIcon, and a named pipe. When the pipe receives something, the icon changes from
yellow to red. The icon tip shows the number of new/total messages received. Left click on
the icon shows a window with the messages, right click on it displays a context menu with
the "Close" command, to stop the service.

The "send" can be used like this: "send list" to list all the
computers in the network (I used Naveen Kohli class
to get the names, thanks a lot), or "send <computer> message".

The service can be installed/removed from the prompt: "service -install" ,
"service -remove", and started from the control panel (the "Services"
icon). I used Craig Link’s example found in MSDN November 1998, but I changed it to suit
my needs. I will comment the code in the the ServiceStart function, because the rest of
the service’s functions (service_ctrl, service_main etc.) are classics.

The function creates first a thread that is responsible for the icon’s parent, a simple
dialogbox. To hide the dialog:

   SetWindowPos(hwndDlg,NULL,-10,-10,0,0,SWP_NOZORDER|SWP_NOMOVE);

and of course the trick with the invisible modless parent to prevent from appearing in
the task bar (this one also not visible – from the resources):

   HWND
hwnd=CreateDialog(NULL,MAKEINTRESOURCE(IDD_DIALOG1),NULL,NULL);

The dialog’s DialogProc has nothing special. On WM_INITDIALOG it displays the icon, on
WM_ICON_NOTIFY – LBUTTON it creates a frame with an edit in it, on WM_ICON_NOTIFY –
RBUTTON shows a context menu, WM_COMMAND – ID_POPUP_CLOSE stops the service, and
WM_CLEARALL and WM_CLOSEFRAME are messages sent by the frame. Every message handling takes
care of the icon also, by changing the icon or the tip.

After creating the thread, the StartService creates a named pipe, and two events – one
to take care of the stop service command and one for the overlapped i/o. After reading
from the pipe, it adds the text read to a buffer and, if the frame is on, it displays the
new message and drops the connection. Right click on the edit clears the text and resets
the icon’s counters.

Downloads

Download service project -44 Kb
Download send project -16 Kb
Download exes – 12 Kb

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