How gethostbyname() getting hostent information? - C / C++ / MFC Discussion Boards

Richard Cheng15-Mar-01 8:13

15-Mar-01 8:13

Hi again,

let me tell you the information again. I have a touchscreen, touchscreen driver, and a MFC program for touchscreen. This MFC program gets data from touchscreen through driver. And driver gets info. from touchscreen through COM port (translate the hex number from COM to something else). Make sense?

Now, MFC programming is talking about events or messages. If there is no message, MFC can do nothing, right? I have to get the notification of ERROR TOUCH. However, then ERROR TOUCH happened, no message sends from Driver to message queue , and MFC keeps silent.

My question is: is there any way to get this data directly from COM port, or do you have any suggestion so that i can get the ERROR TOUCH?

Thanks.

Re: Read data from COM port or Driver???

Erik Funkenbusch15-Mar-01 11:32

Erik Funkenbusch

15-Mar-01 11:32

Well, yes.. you can get the data directly from the COM port, but you'll have to know the format this data uses, and you'll have to disable the driver, since it will own the COM port exclusively.

COM ports act just like files, you open them as files and read from them like files. There are a few functions used to manipulate COM ports that do not apply to files though, these functions are SetCommState and SetCommTimeouts and they take the same file handle used in reading and writing to a file.

Re: Read data from COM port or Driver???

Tim Deveaux15-Mar-01 11:34

Tim Deveaux

15-Mar-01 11:34

Do you have some sort of interface to the driver/lib that you can call at the user level that takes a window handle identifying the window to receive the messages?

You could probably pass AfxGetApp()->m_pMainWnd->m_hWnd as the handle.

Just a thought... not quite sure I understand the setup.

Re: Read data from COM port or Driver??? (again)

Tim Deveaux15-Mar-01 13:58

Tim Deveaux

15-Mar-01 13:58

Hmmm - maybe I misunderstood - you are wondering how to trap a windows message that MFC does not recognize in the class wizard etc - i.e. not a standard windows message.

You can use the message map macros - there are several, like ON_MESSAGE, ON_COMMAND, etc. They presuppose functions with particular signatures, so read the docs on these.

For example, I have a class that changes state - and it is separate from a dialog that needs to be updated when the state changes. Instead of making the class 'know' about the dialog, I define a new message that the class can send, and handle it in the dialog by adding a handler and a message map macro.

I use the ON_MESSAGE macro here:

BEGIN_MESSAGE_MAP(COPCSim1Dlg, CDialog)
    //{{AFX_MSG_MAP(COPCSim1Dlg)
    ON_WM_SYSCOMMAND()
    ON_WM_PAINT()
    /* ... */
    //}}AFX_MSG_MAP
 
    // this is the new one - keep it out of the wizard block above...
    ON_MESSAGE(WM_STATUSCHANGE, OnStatusChange)  
 
END_MESSAGE_MAP()

Then define your handler according to what the macro expects - in this case:

afx_msg LRESULT OnStatusChange(WPARAM, LPARAM);

When something changes, I let the dialog know with PostMessage:

PostMessage(theApp.m_pMainWnd->m_hWnd, WM_STATUSCHANGE, 0, SESSION_CLOSED);

In your case, you'll need to read the docs I guess to figure out what macro you can use. I'm assuming that the driver puts the message in the systems raw input thread and it gets to your window without you having to subscribe to it - and it may even be a standard message with the ERROR TOUCH as one of the parameters by the time it gets to your app - again, you'll need to read the docs. But thought this might help.

For testing, you can add code to PretranslateMessage or DefWindowProc to see if the message is getting through. The macros are a bit more MFC like, and you don't need Class Wizard to use them.

Problem refreshing CListCtrl display

Ken Thomas15-Mar-01 7:12

Ken Thomas

15-Mar-01 7:12

I have a single CListCtrl object on 5 property pages (5 objects). When I minimize my app and then restore it the objects are re-displayed and refreshed as expected. Smile | :)

Here is the problem, if I click on any single entry within the CListCtrl object (any one of the objects on any one of the propery pages) and then minimize the app, when the app is restored the CListCtrl object is not displayed. If I click on another property page and back the CListCtrl object is displayed as I expect. Confused | :confused:

I am stumped.

Dedication to the job at hand.

Adding a button next to...

15-Mar-01 3:18

Hi, i want to add a button next to the buttons at the right top corner (nex to close, minimize, maximize) and use it as "minimize to tray", like in getright.
thanks a lot!

Re: Adding a button next to...

l a u r e n15-Mar-01 23:22

l a u r e n

15-Mar-01 23:22

subclass the mainframe window and add a function to process the button click as well as adding the button in the draw mode Smile | :)

---
"every year we invent better idiot proof systems and every year they invent better idiots"

How gethostbyname() getting hostent information?

Koteswara Rao Perumalla15-Mar-01 2:25

Koteswara Rao Perumalla

15-Mar-01 2:25

Hi,

1. gethostbyname() retrives the host information from host database.what is host database? Is it some file stored on local mechine? How it is giving the information? Or It will query DNS server?
If so, what is the funda behind this?

2. what is DNS server? where can i get more info?

Thanks in advance,
Koteswara Rao, Perumalla
theearth1947@yahoo.com

Re: How gethostbyname() getting hostent information?

Erik Funkenbusch15-Mar-01 11:34

Erik Funkenbusch

15-Mar-01 11:34

Host information can be obtained by several ways:

1) The HOSTS file on the local machine.
2) DNS server response
3) WINS server response
4) DHCP server response

The DNS WINS and DHCP servers are all configured in your local network properties.

Re: How gethostbyname() getting hostent information?

2-May-01 22:27

How to get the nearest NameServer programatocally. I tried to broadcase a message on port 53 using 255.255.255.255 as IP. No response . Why ?

Anita Eugene

Regarding global variables in COM

15-Mar-01 1:55

I tried to have a common variable which would be modified by more than one function of an interface in COM.
But I found that any modification on the variable by one function was not reflected in the other function.
Why is it so?
Is there any way of having a common variable?

Thank You.

Yamuna.E.

Yamuna.E.

Regarding global variables in COM

15-Mar-01 1:55

Regarding global variables in COM

15-Mar-01 1:55

Re: Regarding global variables in COM

Erik Funkenbusch15-Mar-01 11:36

Erik Funkenbusch

15-Mar-01 11:36

Are you trying to use the COM interfaces from multiple programs? If so, the problem is that each COM object is created seperately for each program (usually). If you're talking about the same program, then it could be Thread Local Storage issue.

A single object will generally share it's data between the interface functions.

Re: Regarding global variables in COM

22-Mar-01 17:21

Hi,
I am trying to use the COM interface from multiple programs as you said.Is there any way in this case to have a common variable?
THANK YOU.
Yamuna.E.

Re: Regarding global variables in COM

22-Mar-01 17:24

Hi,
I am trying to use the COM interface from multiple programs as you said.Is there any way in this case to have a common variable?
THANK YOU.
Yamuna.E.

interface

15-Mar-01 0:44

We have developed an Acive X in VC++ and the graphical interface in VB.
We would like to debug both applications at the same time to see how they interact with each other. How can we do it?
There is no problem to debug 2 VC++ applications but not 2 apps from different developing environments.

Thanks in advance Poke tongue | ;-P

Re: interface

Erik Thompson15-Mar-01 7:44

Erik Thompson

15-Mar-01 7:44

Nosotras,

There is an application that has existed from microsoft called WinDBG. In windows 2000 it has gone through vast improvements and has the feature you are looking for to debug and jump between VB and VC code and objects. It's part of the Windows 2000 platform SDK or can be retrieved from the following links...

http://www.microsoft.com/ddk/debugging/installx86.htm

Additional information about WinDBG:
http://msdn.microsoft.com/library/psdk/tools/debugger_5fle.htm
http://www.microsoft.com/ddk/debugging/

Menu and CPropertySheet

14-Mar-01 22:44

How do you display a menu for a CPropertySheet?

Tricky Dialog...

Manfred Ramosch14-Mar-01 22:04

Manfred Ramosch

14-Mar-01 22:04

In my dialog-based application I use some other (modeless) dialogs-boxes
that have the same size than my parent and aligning exactly centered in
my frame-dialog when appearing. ( created with MyDialog->Create() ).
For this behavior I had to use the style 'Child' in the dialog-editor.

For some reason I need one dialog to appear MODAL and so I created the dialog with
MyDialog->DoModal(). If I leave the style 'Child' the dialog totally locks the application
when appearing. So I changed the style to 'Popup'... Now it worked ALMOST like a charm.

One problem left:

When I open the modal dialog it is exactly aligned relative to its parent window.
When I move the parent dialog but still visible on the screen and then open the
modal dialog it also aligns correctly.
But from the moment I move my parent out of the screen so that e.g. only a part of
my parent is visible the modal dialog appears fully visible docked to the edge of
the screen but not aligned to the parent anymore.

Is there any workaround or setting that the modal dialog appears aligned to my parent
even if I move my parent out of the visible part of the screen.
As I created all my dialogs in the application with thin borders and no title-bar
you do never realize that with every view-change a new dialog is created.

Only in the above mentioned situation the thin boarderd-modal-dialog stands alone on
the screen - looking ugly...

Any Ideas on that ?

Manfred

---
'Programming is knowing...'

Re: Tricky Dialog...

James R. Twine15-Mar-01 5:33

James R. Twine

15-Mar-01 5:33

> Is there any workaround or setting that the modal dialog appears aligned to my parent
> even if I move my parent out of the visible part of the screen.

How about obtaining the geometry of your parent window when processing WM_INITDIALOG, and use SetWindowPos() or similar on the modal dialog to the coreect location?

Peace!

-=- James.

Re: Tricky Dialog...

James R. Twine15-Mar-01 5:34

James R. Twine

15-Mar-01 5:34

Re: Tricky Dialog...

James R. Twine15-Mar-01 5:34

James R. Twine

15-Mar-01 5:34

Buy graphic card ...

Hadi Rezaee14-Mar-01 20:37

Hadi Rezaee

14-Mar-01 20:37

<<< In the name of GOD >>>
Hi.
I want to buy 8 MB graphic card.
Please write your comment about it ...
Trident, ATI, ASOOZ, ... ?!!!

Hadi Rezaie

Re: Buy graphic card ...

Christian Graus14-Mar-01 22:36

Christian Graus

14-Mar-01 22:36

AAAARRRRGGGHHHH !!!! All those cards suck. 8 MB cards suck. You need minimum 16 MB if you want to do anything 3D, try brands like nVidia, Voodoo3, Matrox.

Of course, if you have a 386 or something, buy an S3 by all means. I guess you need to also say what you want to do with it...

Christian

The content of this post is not necessarily the opinion of my yadda yadda yadda.

To understand recursion, we must first understand recursion.

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.