Re: Socket connection problem - C / C++ / MFC Discussion Boards

Re: C programming question

Code-o-mat7-Jul-12 9:04

Code-o-mat

7-Jul-12 9:04

Even "youngsters" can have a few tricks up their sleeves. Smile | :)

I also wonder why the OP would need such a thing...maybe he's working with some stripped-down version of C for some egzotic platform that doesn't have sizeof...or it's a school-assignment-type question...

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> If it doesn't matter, it's antimatter.<

Re: C programming question

Richard Andrew x647-Jul-12 10:55

Richard Andrew x64

7-Jul-12 10:55

Psst!

It's spelled "exotic."

The difficult we do right away...
...the impossible takes slightly longer.

Re: C programming question

BCN-1637-Jul-12 16:24

BCN-163

7-Jul-12 16:24

what a perfect way! Thumbs Up | :thumbsup:

Re: C programming question

Code-o-mat7-Jul-12 23:20

Code-o-mat

7-Jul-12 23:20

Thanks

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> If it doesn't matter, it's antimatter.<

Re: C programming question

CPallini8-Jul-12 9:45

CPallini

8-Jul-12 9:45

sizeof operator is the right way. I cannot see the reason for avoiding it.

Veni, vidi, vici.

Re: C programming question

Albert Holguin8-Jul-12 17:12

Albert Holguin

8-Jul-12 17:12

He thinks he can make the wheel rounder... Roll eyes | :rolleyes:

Socket connection problem

ForNow6-Jul-12 3:08

ForNow

6-Jul-12 3:08

Hi,

I have a loop for which I am tryig to connect on four ports for which I only get two
connections I know sometimes sockets take a while to connect

the Creation of the Socket and connection take place in CWinThread Dervived ::Initinstance after the CAsyncSocket objects have been created

Server is a Dos "C" program on the same Windows Vista machine

below is the loop

I am connected thru a router that is kind of old don't know if thats the issue

or If an imporvment in my hardware might help

I put my derived CAsynSocket class inside a a CWinThread class hoping that if such

issues arise I might raise the priority of the thread

looking for any pointers from the experts out there

// loop in CWinApp::Initinstance

C++

  for (i = 0, start_port = 11007; i < 4; start_port++, i++)
{
        threadptr[i] = new SockCLeintThread(start_port);

      if (threadptr[i] == NULL)
         m_pMainWnd->MessageBox("SockClientThreadFail",NULL,MB_ICONERROR);

          threadptr[i]->CreateThread(CREATE_SUSPENDED,0,NULL);

          threadptr[i]->flags.is_connected = 0;

           threadptr[i]->ipaddr = "192.168.1.4";                   // ip address

           SetThreadName(threadptr[i]->m_nThreadID,thread[i]);




          threadptr[i]->ResumeThread();


     }

// My Casynsocket .h file

C++

lass SockClient : public CAsyncSocket
{      
	DECLARE_SERIAL(SockClient)
 public:
      // SockCleint(char *sockptr);
        SockClient(UINT myport);
		SockClient();
		~SockClient();
        char *sockbuffer;		// send and receive buffer
		int num_buff;
		CWnd *send_wnd;
		int thread_no;
		UINT port;
	private:
		int busy;               // inuse
		               // port used by this class
   protected:
                         // window to send message to
        virtual void OnReceive(int nErrorCode);
        virtual void OnSend(int nErrorCode);
        virtual void OnConnect(int nErrorCode);
	virtual void OnClose(int nErrorCode);
}

// my CASynSocket .cpp file

IMPLEMENT_SERIAL(SockClient,CAsyncSocket,VERSIONABLE_SCHEMA | 2)
SockClient::SockClient()
 {
	sockbuffer = new char[300];
//	port = 11007;
 }

SockClient::SockClient(UINT myport)
 {
	 port = myport;
    sockbuffer = new char[300];
//	port = 11007;
 }
SockClient::~SockClient()
{
}
  void SockClient :: OnConnect(int nErrorcode)
  {

	 //   SockCLeintThread* current; 

	 if(nErrorcode == 0)
		 Sockevent.SetEvent();
	 //  SockCLeintThread* current;
	  //   (CWinThread *) current = AfxGetThread();
       UNREFERENCED_PARAMETER(nErrorcode);
          CAsyncSocket::OnConnect(nErrorcode);
       busy = 1;       
  //    if(nErrorcode == WSAETIMEDOUT)
	//	  Connect(current->ipaddr,current->port);

        AsyncSelect(FD_WRITE);
   //    main_app->pevent->SetEvent();
  }
  void SockClient::OnClose(int nErrorCode)                    // SockCLeintThread 
  {
	  SockCLeintThread* current = dynamic_cast<SockCLeintThread*>(current);
 	  current = (SockCLeintThread*)AfxGetThread();
	 //  SockCLeintThread* current;
	  //   (CWinThread *) current = AfxGetThread();
       
       current->flags.is_connected = 0; 
           
           CAsyncSocket::OnClose(nErrorCode);
  }
  void SockClient :: OnSend(int nErrorcode)
  {
	int bytes_sent;
               
      if (num_buff > 0)
	  {
         bytes_sent = Send(sockbuffer,num_buff,0);
         num_buff = num_buff - bytes_sent;
        CAsyncSocket::OnSend(nErrorcode);			
      AsyncSelect(FD_READ);
	  }
 }
   void SockClient::OnReceive(int nErrorcode)
 {
                                               // derived from CAsyncSocket

   static int i=0;

   i++;


   int nRead;
   nRead = Receive(sockbuffer, 4096);

   switch (nRead)
   {
   case 0:
      Close();
      break;
   case SOCKET_ERROR:
      if (GetLastError() != WSAEWOULDBLOCK)
      {
         AfxMessageBox ("Error occurred");
         Close();
      }
      break;
   default:
     num_buff = nRead; //terminate the string

   }
   CAsyncSocket::OnReceive(nErrorcode);
  //  UNREFERENCED_PARAMETER(nErrorcode);
     

    //  Receive(sockbuffer,300,0);

       //  main_app = (CHERC_CMDApp *)AfxGetApp();
         // Post  Event
		 

         send_wnd->SendMessage(WM_RECEIVE_SOCK_MESS,0,(LPARAM)sockbuffer);
        // strncpy(main_app->mytcpipeventptr->command_buffer,sockbuffer,30);


        // main_app->mytcpipeventptr->SetEvent();
 }

// CWinthread .h file

class SockCLeintThread : public CWinThread {
   public:
	      DECLARE_DYNCREATE(SockCLeintThread)
        //		DECLARE_SERIAL(SockCLeintThread)
       //     IMPLEMENT_DYNAMIC(SockCLientThread)
        public:
			     SockCLeintThread(UINT myport);
				 SockCLeintThread();
				~SockCLeintThread();
                CWnd *sendwindow;
                CWnd *call_wnd;
       			char *thread_id;
				 SockClient thisocket;            // Socket to do ocommunication
				 
                void Sendit(WPARAM, LPARAM);
				void Receiveit(WPARAM, LPARAM);
			    LPCTSTR ipaddr;
                BOOL idle;				 // looking for work
			 allexceptions myallexception;
				 
				struct {
					unsigned int is_connected : 1;
					unsigned int busy : 1;
				} flags;
				
protected:
	  virtual BOOL InitInstance();      // Just for starters
           DECLARE_MESSAGE_MAP()
};

// CwinThread .cpp file

IMPLEMENT_DYNCREATE(SockCLeintThread,CWinThread)
BEGIN_MESSAGE_MAP(SockCLeintThread, CWinThread)
     //{{AFX_MSG_MAP(CMyThread)
         ON_THREAD_MESSAGE(WM_SEND_SOCK_MESS,Sendit)
      //   ON_THREAD_MESSAGE(WM_SOCKET_NOTIFY,sockoper)
     // NOTE - the ClassWizard will add and remove mapping macros here.
       //  ON_THREAD_MESSAGE ( WM_MYTHREADMESSAGE, MyMessageHandler )
     //}}AFX_MSG_MAP
     END_MESSAGE_MAP()

void SockCLeintThread::Sendit(WPARAM count, LPARAM command)
{
                UNREFERENCED_PARAMETER(command);
    //  thisocket.AsyncSelect(FD_READ|FD_WRITE);
			    thisocket.num_buff = count;
				thisocket.AsyncSelect(FD_WRITE);
        //      strncpy(thisocket.sockbuffer,(char *)command,20);
				return;
}

void SockCLeintThread::Receiveit(WPARAM count, LPARAM command)
{
      UNREFERENCED_PARAMETER(count);
          UNREFERENCED_PARAMETER(command);
        thisocket.num_buff = 0;
}


SockCLeintThread::SockCLeintThread() 
{
//	thisocket = new SockClient;
//	 if (thisocket == NULL)
//			 this->m_pMainWnd->MessageBox("Socket","Socket Error",MB_ICONERROR);

//        ipaddr = "192.168.1.4";
	// thisocket(myport); 
        m_bAutoDelete = FALSE;
}
SockCLeintThread::SockCLeintThread(UINT myport) : thisocket(myport)
{
//	thisocket = new SockClient;
//	 if (thisocket == NULL)
//			 this->m_pMainWnd->MessageBox("Socket","Socket Error",MB_ICONERROR);

//        ipaddr = "192.168.1.4";
	// thisocket(myport); 
        m_bAutoDelete = FALSE;
}

SockCLeintThread::~SockCLeintThread()
{
}

BOOL SockCLeintThread::InitInstance()
   {
int error_code;
MSG m_msgCur;
extern void SetThreadName( DWORD dwThreadID, LPCSTR szThreadName);
  
           socklock.Lock();

		  

          	 	 if(thisocket.Create(thisocket.port,SOCK_STREAM,NULL)== 0)
          {
                          error_code =  GetLastError();
                   }

              if (thisocket.AsyncSelect(FD_READ|FD_WRITE|FD_CONNECT|FD_CLOSE|FD_OOB|FD_ACCEPT) == 0) 
 			                   error_code =  GetLastError();
			 

       

          
      //    WaitForSingleObject(Sockevent.m_hObject,INFINITE);

           if( thisocket.Connect(ipaddr,thisocket.port) == 0)
                  {
 		                         error_code =  GetLastError();
                   }
 		   else
 				 	  flags.is_connected = 1;
		  
			socklock.Unlock();   
  PeekMessage(&m_msgCur, NULL, NULL, NULL, PM_NOREMOVE);   // Create Message Queue



    return TRUE;                                                   // [11]
   }

Re: Socket connection problem

Albert Holguin6-Jul-12 4:15

Albert Holguin

6-Jul-12 4:15

Not sure what you're asking, this looks like a bit of a code dump. Typically connections won't take very long if you're within the same LAN, so you may have another issue with your code. By the way, if you're using an asynchronous socket, the connection is also asynchronous, meaning you don't sit there and wait for a response, the callback will be called when it's either connected or timed out.

ForNow wrote:
PeekMessage(&m_msgCur, NULL, NULL, NULL, PM_NOREMOVE);

You don't have to manually create a message queue for a CWinThread.

Re: Socket connection problem

ForNow6-Jul-12 6:57

ForNow

6-Jul-12 6:57

You are right the CAsynSocket::OnConnect should be called by the framework one way or another at the very least with a WSAETIMEDOUT nErrorCode

I should put a TRACE in to printf the nerrorcode

Re: Socket connection problem

fat_boy6-Jul-12 5:53

fat_boy

6-Jul-12 5:53

Could you post some code? Wink | ;)

Reading Buffer of unicode and ansi character

john56326-Jul-12 0:06

john5632

6-Jul-12 0:06

I am recieving a buffer which is having unicode and ansi character. How can I read it so that I can get the actual string.

Re: Reading Buffer of unicode and ansi character

Jochen Arndt6-Jul-12 0:22

Jochen Arndt

6-Jul-12 0:22

Please be a little bit more specific (e.g. by providing an example). Do you have a buffer that may contain an ANSI or Unicode (Microsoft wide character UTF16-LE, UTF16-BE, or UTF-8) string and you want to detect the encoding? If so, do you know the length of the buffer?

Re: Reading Buffer of unicode and ansi character

john56326-Jul-12 0:39

john5632

6-Jul-12 0:39

Yes you are right and I know the lenght of buffer.

Re: Reading Buffer of unicode and ansi character

Jochen Arndt6-Jul-12 0:56

Jochen Arndt

6-Jul-12 0:56

Wide char strings stored in files usually begin with a BOM (Byte Order Mark)[^].

If there is no BOM in your case, use the ANSI strlen() function and compare the result with the buffer length without NULL bytes. If it matches, the string is ANSI or UTF-8. If not, it is probably a wide char string. For Microsoft Unicode (UTF-16LE), this can be verified by comparing the return value of wcslen() with the buffer length (multiply returned length by two / sizeof(wchar_t)).

This solution requires that the string in the buffer is NULL terminated. If not, create a new buffer with length + 2, copy the data and append two NULL bytes (two bytes to have a valid terminated wide char string).

If the strings in the buffer are NULL terminated, you may also look for two NULL bytes at the end of UTF-16 strings.

Re: Reading Buffer of unicode and ansi character

john56326-Jul-12 1:09

john5632

6-Jul-12 1:09

Thanks for your help but I dont know how to check BOM..can you show by example...

Re: Reading Buffer of unicode and ansi character

Jochen Arndt6-Jul-12 1:18

Jochen Arndt

6-Jul-12 1:18

Detecting code page from BOM:

C++

UINT nCP = 0; // CP_ACP
if (0 == memcmp(lpszBuf, "\xEF\xBB\xBF", 3))
    nCP = CP_UTF8;
else if (0 == memcmp(lpszBuf, "\xFF\xFE", 2))
    nCP = 1200; // UTF-16LE
else if (0 == memcmp(lpszBuf, "\xFE\xFF", 2))
    nCP = 1201; // UTF-16BE

However, this requires the presence of a BOM. With text files, there should be one for UTF-16 and may be one with UTF-8. If you get your data from elsewhere (e.g. as network package), there may be no BOM.

Re: Reading Buffer of unicode and ansi character

john56326-Jul-12 1:31

john5632

6-Jul-12 1:31

It will comapare the byte with 0xFFFE, 0xFEFF but my problem is to seperate out ANSI and UNICODE string from a BYTE buffer.

My buffer will will be like "ConnectInfo?ã„·ã„´??56.58.98.142?fgg?n?v HTT". In this buffer unicode data is "ã„·ã„´" and remaining data is in ANSI.
I need to seperate out the data and need to create a complete string of unicode characters.

Re: Reading Buffer of unicode and ansi character

Jochen Arndt6-Jul-12 1:52

Jochen Arndt

6-Jul-12 1:52

That's why I asked for an example in my first post:
Your string seems to be UTF-8 encoded.

To decode it you can use MultiByteToWideChar() which converts it to a wide char string:

C++

// Assuming nLen is length including trailing NULL byte
// Get length of wide char string
int nWideLen = ::MultiByteToWideChar(CP_UTF8, 0, lpszBuf, nLen, NULL, 0);
wchar_t *lpszWide = new wchar_t[nWideLen];
::MultiByteToWideChar(CP_UTF8, 0, lpszBuf, nLen, lpszWide, nWideLen);
// Use string lpszWide
delete [] lpszWide;

Re: Reading Buffer of unicode and ansi character

BCN-1637-Jul-12 16:32

BCN-163

7-Jul-12 16:32

execuse me. where can I get some data about encoding. actualy, I don't know exactly what's the different between UTF8 and UNICODE. Thank you very much

Re: Reading Buffer of unicode and ansi character

Jochen Arndt7-Jul-12 22:28

Jochen Arndt

7-Jul-12 22:28

Good starting points for such questions are Google and Wikipedia. For Unicode, they should both bring you to www.unicode.org.

Unicode is the standard and UTF-8 is one Unicode Transformation Format. Another encoding format is UTF-16LE which is used by Microsoft Windows (WCHAR and wchar_t types). When you read Unicode in Microsoft documentation, it refers mostly to the internally used UTF-16LE format.

Re: Reading Buffer of unicode and ansi character

BCN-1638-Jul-12 2:36

BCN-163

8-Jul-12 2:36

thank you very much. what I really want to know is the details which may have some help for work. I will visit the site, thanks again.

Programming Problem

Ahmed Charfeddine5-Jul-12 22:54

Ahmed Charfeddine

5-Jul-12 22:54

We have a collection of items C(x)
A thread A is responsible for performing tasks for those items in a continous and circular way.
In coding terms, we would write :

void doWork() // function executed by thread A
{
	while(true)
	{
		for each x in C(x)
			perform task(x).
	}
}

We have other threads, that write and remove items from C(x) :

void remove(x);
void Add(x);

Now comes the final specification :

The function task(x), returns either true or false. If false is returned, then it means, there no need to call task(x) for the same x
in the future, unless some thread makes a signal for us that the thread A should be processing all element x.

let's call this notification function :

void NotifyIncludeAllElements();

What is the best approach here ?

Push Framework - now released !
http://www.pushframework.com

Re: Programming Problem

«_Superman_»6-Jul-12 17:55

«_Superman_»

6-Jul-12 17:55

x can be a structure variable -

struct _tagX
{
    ... Xdata;
    ...
    bool process;
};

Now process can be used as a flag to decide if processing is needed.

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Re: Programming Problem

Ahmed Charfeddine7-Jul-12 0:25

Ahmed Charfeddine

7-Jul-12 0:25

The size of collection C(X) can be so much big, that we might be interested in isolate the elements that are temporarily ignored, in another collection.

Further more, if all items are ignored, i am hoping that thread A blocks and not consume CPU for nothing.

Finally, the rate of calls to NotifyIncludeAllElements can be so much high, that if we make a shared lock with thread A there, then the performance of processing of A is greatly affected.

I tried to think about semaphore, signals, CAS operations, but came up with particular solution, you ca see it in this class I called AbstractDistributor : (Link to CodePlex)
http://pushframework.codeplex.com/SourceControl/changeset/view/98598#1909758[^]

When I think about the problem I can see many real world scenarios applicable to it. I am wondering if it is already solved in a good way.

Push Framework - now released !
http://www.pushframework.com

Format INT_MAX

_Flaviu5-Jul-12 22:53

_Flaviu

5-Jul-12 22:53

I have follow code :

C++

m_sHex.Format(_T("FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF")); // max value for 32 bit

char* p = NULL;
const int nDec = strtol(m_sHex, &p, 16);
sUDec.Format(_T("%u"), nDec);
sDec.Format(_T("%d"), nDec);

and sUDec is '65535' and sDec is '65535' ... I expected to see sUDec 4.294.967.295 and sDec -1 ... what I'm missing ?

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