Sharing data among Threads - C / C++ / MFC Discussion Boards

hph17-Mar-04 4:28

17-Mar-04 4:28

hi,

"rhs" is just the name of the input parameter, you can also use "cat" if you want, but only if you like cats Wink | ;-)

Have a nice day!
hph

Including project files from library

Cedric Moonen17-Mar-04 4:19

Cedric Moonen

17-Mar-04 4:19

Hi !

I need to design a class that will encapsulate an ActiveX object (a chart control). I want to put these files (the .h and the .cpp files) in a library common to all of my projects so I can reuse this class.
The problem is that the files for the ActiveX object need to be in the project directory (I use Add To Project->Components and Control to add the ActiveX to my project).
Is there a macro that I can use like the following way:

#include "CURRENT_PROJECT_DIRECTORY\CChart.h"

in order to access the current project directory from a file within my library ??

The files for the ActiveX cannot be copied in the library. Any idea ??

OpenProcess

hph17-Mar-04 4:03

hph

17-Mar-04 4:03

Hello,

can someone tell me the meaning of the SYNCHRONIZE flag which can be used in OpenProcess ?

Thanks in advance!

Re: OpenProcess

gUrM33T17-Mar-04 14:57

gUrM33T

17-Mar-04 14:57

This flag allows you to use the process handle in any of the wait functions to wait for the process to terminate. BTW, it is available in Windows NT/2000 or later only.

Gurmeet S. Kochar

If you believe in God, it's because of the Devil

Windows NT Device Driver and PCI Bus access on Windows NT

BhaskarBora17-Mar-04 3:57

BhaskarBora

17-Mar-04 3:57

Hi there

I am in need for the following information.

1. Any specific link where i can find info for writing Device-Drivers on Win NT.
2. Link where PCI bus access on Win NT is explained.

thanks in advance...
Bhaskar...

___________________________
When a thing is new, people say, "It's not true." Later, when its truth becomes obvious, people say, "It's not important." Finally, when its importance cannot be denied, people say, "Well, it's not new."

How to creat a graphical back ground and button on a dialog class in MFC?

flow555517-Mar-04 2:58

flow5555

17-Mar-04 2:58

Hey there everyone,

I am a new member of the forum and relatively new to MFC. What I like to know how to create a graphical background and button.

If anyone can gave a specific example or link that will help, it will be very apperciated.

Thanks, Smile | :)

Re: How to creat a graphical back ground and button on a dialog class in MFC?

David Crow17-Mar-04 4:33

David Crow

17-Mar-04 4:33

See if either of these help:

http://www.voidnish.com/articles/ShowArticle.aspx?code=bmpdlg01
http://www.flounder.com/bitmapbutton.htm

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Sharing data among Threads

Cedric Moonen17-Mar-04 2:44

Cedric Moonen

17-Mar-04 2:44

Hello all!

I have a project designed with the MFC document/view architecture. In the App idle time I read some data from a data source (I call a function of my doc class). This data will be displayed in a chart.
But I need also to make some computation on this data but I want to make this in a separate thread (the computation take some times and it cannot stop the reading of the data).
When I start the new Thread, I pass a pointer to my document so it can access data and the data will be stored in a buffer (FIFO buffer).
I was wondering if this is safe to do such a thing ?

Something like that:

BOOL CMyAppDoc::idle()
{
   // read data here
   pFIFOBuffer->AddData(Data);
}

And in the thread function:

//....
pMyDoc->ComputeData();
//...

void CMyAppDoc::ComputeData()
{
    while (TRUE)
        if (pFIFOBuffer->GetData(Data))
            ProcessData(Data);
}

Thanks

Re: Sharing data among Threads

GuimaSun17-Mar-04 3:13

GuimaSun

17-Mar-04 3:13

Some tips:

You must use code to protect multiple multithreading access to any shared data, like critical sections:
CRITICAL_SECTION cs;
InitializeCriticalSection( &cs );
...
EnterCriticalSection( & cs );
shared data access
LeaveCriticalSection( & cs );

You can also use Event primitives to signal end processing, like: CreateEvent, SetEvent, ResetEvent and WaitForSingleObject.

Good luck Smile | :)

GuimaSun
www.nexsun.com.br

Re: Sharing data among Threads

Cedric Moonen17-Mar-04 3:31

Cedric Moonen

17-Mar-04 3:31

Thanks !
Yes I think I will use the critical section, that's easy to use and fit perfectly with my needs.

Thanks Smile | :)

URL opens application

Florin Ochiana17-Mar-04 1:49

Florin Ochiana

17-Mar-04 1:49

Hi,

I want to put in a site links that would start my application. Something like yahoo has in the profile pages:

ymsgr:sendIM?yahoouser

I know how to make a handle that will send the call to my app using something like myapp:command?parameter but what do I have to do in my app to catch that command and get the parameter?

Thanks

-----
We are what we repeatedly do. Excellence, then, is not an act, but a habit.

How to use CheckMenuItem()????????

Anonymous17-Mar-04 1:46

Anonymous

17-Mar-04 1:46

Hi I would like to palce a check mark for menu item, if user clicks a menu item. I would like to do this from CMainFrm class.Can u please give me an idea?

Thanks
JP Poke tongue | ;-P

Re: How to use CheckMenuItem()????????

Florin Ochiana17-Mar-04 2:00

Florin Ochiana

17-Mar-04 2:00

You have to have a function that would execute the code when the users selects the menu item.

Let's say it's

ON_COMMAND(ID_YOURMENUITEM, TestFn)

Maybe you want to use a global variable that will tell you the state of that item.

bool testVar;

void TestFn() {
CMenu *m_MainMenu;
// let's say you have your menu in m_MainMenu

if (testVar) {
testVar = false;
m_MainMenu->GetSubMenu(1)->GetSubMenu(x)->CheckMenuItem(n, MF_BYPOSITION | MF_UNCHECKED);
} else {
testVar = true;
m_MainMenu->GetSubMenu(1)->GetSubMenu(x)->CheckMenuItem(n, MF_BYPOSITION | MF_CHECKED);
}
}

where n is the position of your item in the menu

-----
We are what we repeatedly do. Excellence, then, is not an act, but a habit.

Re: How to use CheckMenuItem()????????

Anonymous17-Mar-04 2:10

Anonymous

17-Mar-04 2:10

Hey
In above example, m_MainMenu is unreferenced..so that code is not working. How to attach my Mainmeu to this?

Thanks
JP

Re: How to use CheckMenuItem()????????

Florin Ochiana17-Mar-04 2:19

Florin Ochiana

17-Mar-04 2:19

I told you that m_MainMenu is your menu. You will have to replace it with your variable.

If it's the apps menu then you have to do something like this
m_MainMenu = GetMenu();

-----
We are what we repeatedly do. Excellence, then, is not an act, but a habit.

Thank u very much!!

Anonymous17-Mar-04 2:39

Anonymous

17-Mar-04 2:39

Thank u very much!!

Re: How to use CheckMenuItem()????????

Maximilien17-Mar-04 2:33

Maximilien

17-Mar-04 2:33

Use the ON_UPDATE_COMMAND_UI message if possible.

...
ON_UPDATE_COMMAND_UI(IDM_YOUR_MENU_ITEM, OnUpdateYourMenuItem)
...

void CMainFrm::OnUpdateYourMenuItem(CCmdUI* pCmdUI) 
{
  pCmdUI->SetCheck( IsMenuItemCheck() );
}

Maximilien Lincourt
Your Head A Splode - Strong Bad

cin >> question

ns17-Mar-04 1:16

17-Mar-04 1:16

I am reading from 2 datafiles with three entries:

File 1:
--------
abc
def
ghi
--------

file 2: has an extra blank line after ghi
---------
abc
def
ghi

--------

If I have an ifstream object 'fin' and I do

char val;
while (!fin.eof())
{
fin >> val;

cout << val;
}

For file 1 I get the output as
abc
def
ghi

as expected.

But for file 2 I get

abc
def
ghi
ghi

1.Why is this?

2.How can I prevent it from processing any extra blank lines?

thanks,
ns

Re: cin >> question

David Crow17-Mar-04 2:27

David Crow

17-Mar-04 2:27

Using getline() might help.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: cin >> question

Anonymous17-Mar-04 22:11

Anonymous

17-Mar-04 22:11

use cin.get()....or create cstyle file operations...
create FILE*....
use fgetc(fp)....

Re: cin >> question

David Crow19-Mar-04 3:25

David Crow

19-Mar-04 3:25

Right, but you should probably direct this towards the OP, otherwise your suggestion will possibly go unseen.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Property sheets and pages

Anonymous17-Mar-04 0:56

Anonymous

17-Mar-04 0:56

Hi
I have created a property sheet and some property pages.

My property page is user details and to avoid one big dialog I used property pages to split it up so I have address on one page contact info on another page and so on.

Can my pages access the sheet in any way?

I want my sheet to provide functions to save and load my user details so that changes to any of my pages calls the functions provided by the sheet. This is much easier than saving and loading for each page. I could have a function called load() in my property sheet which I could then call from any property page.

Now I have one file to store all my user details in but one easy way is to have a separate file for each property page but that means having several files where I only had one before.

Re: Property sheets and pages

Nirav Doshi17-Mar-04 1:28

Nirav Doshi

17-Mar-04 1:28

Anonymous wrote:
Can my pages access the sheet in any way?

* Try:

CMySheet	*pSheet  = ((CMySheet *) GetParent());

-OR-

CMySheet	*pSheet  = ((CMySheet *) GetOwner());

* And for your dialog in which you have the sheet, you can have:

CMyDialog	*pDialog = ((CMyDialog *) GetParentOwner());

The reason I have answered the second one is if you want to access your sheet through your dialog, as pDialog->pMySheet, this could help!

- Nirav

* Don't wish it was easier, wish you were better! *

Re: Property sheets and pages

thowra17-Mar-04 1:52

thowra

17-Mar-04 1:52

Assuming your property sheet has each page as a member, you should be able to pass data to each page on initialisation and read data back from each page before your property page closes using simple member functions defined for each page.

If in your case you have a user object, it can handle a single file for you which is how it should be done of course, and your property sheet can call the user object's load() function at initialisation, you then pass a pointer to the user object to each of your pages and they can read and modify data using the member functions the user object provides or you could just pass them the values of the user objects. Before your property sheet closes, it can then call the user object's save() function if any modifications have been made.

e.g.:

MyPropSheet.h:

CMyPropPage1 m_MyPropPage1
CMyPropPage2 m_MyPropPage2

MyPropSheet.cpp:

CMyUser myUser;
myUser.Load();
m_MyPropPage1.setUser(&myUser)
m_MyPropPage2.setUser(&myUser)
AddPage(&m_MyPropPage1);
AddPage(&m_MyPropPage2);

"The folly of man is that he dreams of what he can never achieve rather than dream of what he can."

"If you think education is expensive, try ignorance."

Detecting if a print job failed

tcss16-Mar-04 23:58

tcss

16-Mar-04 23:58

How can I determine if a print job was not printed. (ie the printer was off or out of paper). Currently if the printer is off the usual mechanism put the job in the queue and the print manager askes the retry of cancel question. As this is for a stock control label, I need to know if it printed OK.
I do not need a complete solution, just a starting point as this is a new area for me. I do not have to much of a clue where to start looking.

The openprinter
StartDocPrinter
StartPagePrinter
WritePrinter
EndPagePrinter
EndDocPrinter
ClosePrinter
etc functions all gibe a good return code too.

Any pinters welcome

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