C / C++ / MFC

Re: One more thing forgot

30-Jun-15 12:58

Sorry
But my question is can I call
UpdateData from anywhere or does it have to be from CDialog::Oninitdialig

Richard MacCutchan1-Jul-15 0:22

Richard MacCutchan

1-Jul-15 0:22

You can call it from anywhere. You usually call it first from CDialog::OnInitDialog to set the initial values of the variables. Then you call it at other times, in response to user input to save any new values.

David Crow30-Jun-15 16:43

David Crow

30-Jun-15 16:43

ForNow wrote:
I have a CStatic ptr says
CStatic *mytext

Why use a pointer? Just add:

CStatic mytext;

to your dialog's header file. Add an entry to your dialog's DoDataExchange() method like:

DDX_Control(pDX, IDC_MYTEXT, mytext);

Then in your dialog's OnInitDialog() method, set the control's text like:

mytext.SetWindowText(_T("Hello World"));

And that's it! No need for pointers, memory allocation, or messy calls to UpdateData().

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ForNow30-Jun-15 17:06

30-Jun-15 17:06

Thanks in a related question if I wanted to change the font of the text I'm guessing I would do that in a the OnCtlColor would I use pWnd->SetFont (of course after I created a font) with CreateFontIndirect or would I use the pDC and do pDC->SelectObject

Thanks

David Crow1-Jul-15 2:03

David Crow

1-Jul-15 2:03

See the "Bold static controls" section of this article.

ForNow1-Jul-15 3:36

1-Jul-15 3:36

You are really helpful I am going to press my luck and ask the following if the variable was a CString using DDX_Text as per jeron1 would I then look to change The font in OnCtlColor

Thanks

Thanks

David Crow1-Jul-15 3:41

David Crow

1-Jul-15 3:41

I do not know. In 23 years of using MFC, I've never used a CString as an interface to a static control. Give it a whirl and let us know how it works.

jeron11-Jul-15 4:04

jeron1

1-Jul-15 4:04

I can't imagine setting or changing the font color being affected by the type of variable (CString or CStatic)associated with the control.

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ForNow1-Jul-15 5:19

1-Jul-15 5:19

I was just looking to change the font of a control associated with a CString
David's suggestion would work if I associated the control with a CStatic CWnd object
Thanks

jeron11-Jul-15 5:59

jeron1

1-Jul-15 5:59

Another way could be like something shown here[^].

ForNow1-Jul-15 10:21

1-Jul-15 10:21

http://www.flounder.com/viewfont.htm[^]

Would I need to implement WM_SETFONT WM_GETFONT as per this article

jeron11-Jul-15 11:32

jeron1

1-Jul-15 11:32

How often are you changing fonts? Once? if so just call SetFont(...) on the static control object in the OnInitDialog() handler and be done with it (make sure the CFont object is a member of the dialog class). After that you can call SetWindowText() whenever you want. Should be quick enough to try.

ForNow1-Jul-15 12:19

1-Jul-15 12:19

I agree the only things I was adding is the I have to add the message handlers to my CDialog derived for it work per day he article

Thanks will try Tommrow

ForNow2-Jul-15 13:27

2-Jul-15 13:27

jeron1 just wanted to thank you I couldn't get anything going with DDX_Control/CStatic
but the DDX_Text/CString worked out great

Thanks

recv no blocking

mosine29-Jun-15 21:33

29-Jun-15 21:33

Hi,
I'm developing a server multithread (multiclient) and I have a problem with recv function (c language - SO: windows).
My clients send info to server every 5 seconds and recv function blocks thread until info arrives. I try with ioctlsocket, but the number of byte read always is 0; I try with flag MSG_PEEK, but the data is copied into the buffer, but is not removed from the input queue and so I have many messages.
Is there a way to perform recv function no blocking?
THANKS

CPallini29-Jun-15 21:54

29-Jun-15 21:54

Usually a blocking recv is not a problem at all in a multithreaded application: the receiving thread blocks but the other threads keep runnning and the application is responsive.
On the other hand, as you may find in the documentation[^], you might use non blocking mode on sockets, however, I guess, your application would be more involved.

mosine29-Jun-15 22:21

29-Jun-15 22:21

Thanks for reply.
The problem is, if my server must send data to client, it waits 5 seconds because recv function blocks thread.
I try to launch another thread (for each client) for send operation, but cpu works 100%.

CPallini29-Jun-15 22:35

29-Jun-15 22:35

Quote:
The problem is, if my server must send data to client, it waits 5 seconds because recv function blocks thread.

As far as I know, the server's send is not blocked by the client recv.

Quote:
I try to launch another thread (for each client) for send operation, but cpu works 100%.

Waiting on I/O operations should not consume CPU, there's probably a flawn in your code.

mosine29-Jun-15 22:52

29-Jun-15 22:52

I post my code:

DWORD  WINAPI cliTh1( LPVOID lpData ){
    struct CLIENT_INFO *pClientInfo;
    char szClientMsg[250];
    char packet[50];
    HANDLE clientTxThread;

    pClientInfo = (struct CLIENT_INFO *)lpData ;
    char *ip = inet_ntoa(pClientInfo->clientAddr.sin_addr);
    printf("SOCKET:%d  - IP:%s  - THREAD_ID:%ld\n", pClientInfo->hClientSocket, ip   
                                                   ,GetCurrentThreadId());
    Q->pClient = pClientInfo;
    pClientInfo->primaConn = 0;
    pClientInfo->indirizzo = 0;
    pClientInfo->p = getDisconnect;
    while ( 1 ){
        if(j>=MAXELEMENTS){j=0;};
        if(WSAGetLastError()){
            if(pClientInfo->primaConn == 1){
                disconnectBuffer[pClientInfo->indirizzo] = 1;
                pClientInfo->primaConn=0;
            }
            if(disconnectBuffer[pClientInfo->indirizzo] == 1){
                creaPackDisc(packet, pClientInfo->indirizzo);
                strcpy(bufferRx[j].packet, packet);
                Enqueue(Q,  packet);
                j++;
            }else{
                closesocket(pClientInfo->hClientSocket);
                ExitThread(pClientInfo->txThId);
                ExitThread(GetCurrentThreadId());
            }
            Sleep(1000);
        }else{
            if((pClientInfo->primaConn == 0) && (pClientInfo->indirizzo != 0)){
                pClientInfo->connessione = setConnect(GetCurrentThreadId(), pClientInfo->indirizzo, ip);
                if(pClientInfo->connessione == 1){
                    pClientInfo->primaConn = 1;
                }
                //THREAD TX for each client
                clientTxThread = CreateThread(NULL,0,(LPTHREAD_START_ROUTINE)txThread, 
                                              pClientInfo,0,&pClientInfo->txThId);
                if ( clientTxThread == NULL ){
                    printf("Unable to create client thread");
                } else {
                    CloseHandle( clientTxThread ) ;
                }
            }
            if(recv( pClientInfo -> hClientSocket, szClientMsg, sizeof( szClientMsg ), 0  ) > 0){
                strcpy(bufferRx[j].packet, szClientMsg);
                memset(&szClientMsg[0], 0, sizeof(szClientMsg));
                pClientInfo->indirizzo = calcolaHighLow(bufferRx[j].packet[1], bufferRx[j].packet[2],  
                                                       bufferRx[j].packet[3], bufferRx[j].packet[4]);
                Enqueue(Q,  bufferRx[j].packet);
                j++;
                strncpy(message, "ACK\n\r",5);
                send(pClientInfo -> hClientSocket , message , 5 , 0);
            }
        }
    }
    return(TRUE);
}

CPU works 100% with this solution.

CPallini29-Jun-15 23:01

29-Jun-15 23:01

Are you testing with both client and server running on the same machine? Have a look at this thread: "send and recv are cpu intensive?"[^].

mosine29-Jun-15 23:06

29-Jun-15 23:06

Yes, I'm testing <n> clients with server on the same machine. My goal is: if the system works fine on my pc, I will have no problems on server machine.
Is there a minimal example of recv no blocking?

CPallini29-Jun-15 23:24

29-Jun-15 23:24

Did you read the linked page? It is normal a 100% CPU usage if they both run on the same machine.

Daniel Pfeffer30-Jun-15 8:12

Daniel Pfeffer

30-Jun-15 8:12

If you only have one physical machine, I suggest installing Windows in a virtual machine, and running one of the tasks there. That would ensure that the platforms are separate, and would help you to track down the 100% CPU issue.

IMO, a multithreaded blocking recv() implementation is conceptually much simpler than a non-blocking recv() implementation.

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Albert Holguin30-Jun-15 13:26

Albert Holguin

30-Jun-15 13:26

Daniel Pfeffer wrote:
IMO, a multithreaded blocking recv() implementation is conceptually much simpler than a non-blocking recv() implementation.

Yep, and it works really well... just be careful for hanging sockets in Linux.

Daniel Pfeffer wrote:
If you only have one physical machine, I suggest installing Windows in a virtual machine, and running one of the tasks there. That would ensure that the platforms are separate, and would help you to track down the 100% CPU issue.

This might actually yield the same result. The issue is the super low latency in the network when everything is co-located. Essentially if you're tx and rx run as fast as possible, it could take up all the CPU time available.

modified 30-Jun-15 19:41pm.