Re: how to establish usb communication in MFC? - C / C++ / MFC Discussion Boards

Andy2026-Sep-07 10:58

6-Sep-07 10:58

If I comment out the receive I get error 10057 on the send.

All I want to do is transmit a UDP message at 10Hz. The client can be running or not. I will use port 5001, but I do not need to know the client PC.

The client will need to know both Port and PC - correct?

Andy.

Re: UDP Server

Mark Salsbery6-Sep-07 11:33

Mark Salsbery

6-Sep-07 11:33

Andy202 wrote:
If I comment out the receive I get error 10057 on the send.

The error is WSAENOTCONN.
That's expected since you're using the "from" address from the recvfrom(),
which isn't going to be a valid address without a successful recvfrom() call.

Andy202 wrote:
I would like my UDP server to send the data when the client connects;

UDP is connectionless so you don't know if a client is connected or not.

It sounds like you need to either...

1) Keep track of clients that are listening - that would mean a client has to send a notification to
the server when it's ready to receive datagrams. The server can store a list of "connected" clients and
send the periodic datagrams to every address on the list.

2) Broadcast the periodic datagrams. Set the socket option SO_BROADCAST on the socket and send
to the broadcast address (INADDR_BROADCAST). The clients need to set the SO_BROADCAST socket option
as well.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: UDP Server

Andy2027-Sep-07 4:48

Andy202

7-Sep-07 4:48

Thanks again for your Post Mark, I now get Error = 10057 when the Client is not running and Error = 10093 when the Client is running.

// Setup port addresses<br />
local.sin_family = AF_INET;<br />
local.sin_addr.s_addr = INADDR_BROADCAST;<br />
local.sin_port = htons(port);<br />
<br />
conn_socket = socket(AF_INET, socket_type, 0); /* Open a socket */<br />
<br />
if (setsockopt (conn_socket, SOL_SOCKET, SO_BROADCAST, (char *) &TxBuffer, sizeof (TxBuffer)) == SOCKET_ERROR)<br />
{<br />
	closesocket (conn_socket);<br />
	g_szFormatting.Format("setsockopt() failed: %d\n",WSAGetLastError());<br />
	ReportMessages(g_szFormatting);<br />
	WSACleanup();<br />
	return false;<br />
}<br />
<br />
//Make it so you can attach more than one thing to a socket<br />
if (setsockopt (conn_socket, SOL_SOCKET, SO_REUSEADDR , (char *) &optval, sizeof(optval))  == SOCKET_ERROR)<br />
{				<br />
	g_szFormatting.Format("Couldn't set SO_REUSEADDR %d\n ", WSAGetLastError());<br />
	ReportMessages(g_szFormatting);<br />
	closesocket (conn_socket);<br />
	WSACleanup();<br />
	return false;<br />
}

And in the Writer Thread:-

while(g_bUDP_Socket_Created && g_bUDPStatus)<br />
{<br />
<br />
retval = sendto (conn_socket, (char*)TxBuffer, sizeof(Tx_Data), 0, NULL , 0);<br />
	if (retval == SOCKET_ERROR)<br />
	{	<br />
		g_szFormatting.Format("Couldn't send data, %d",WSAGetLastError());<br />
		::MessageBox((HWND)NULL,g_szFormatting, NULL,MB_ICONEXCLAMATION );<br />
		closesocket (conn_socket);<br />
		WSACleanup();<br />
	}<br />
	Sleep(1000);<br />
}<br />
// Close the Winsock and tidy up<br />
closesocket(conn_socket);<br />
WSACleanup();

Re: UDP Server

Mark Salsbery7-Sep-07 5:22

Mark Salsbery

7-Sep-07 5:22

Error 10093 WSANOTINITIALISED Successful WSAStartup not yet performed

Also...

You need to create a proper UDP socket:

conn_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP

); /* Open a socket */<br />
<br />

and sendto() needs a destination address.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: UDP Server

Andy2027-Sep-07 9:13

Andy202

7-Sep-07 9:13

One final question Mark, if I just want to Broadcast UDP packets out on a local network, what destination address do I use?

Re: UDP Server

Moak8-Nov-07 12:37

Moak

8-Nov-07 12:37

Andy202 wrote:
I just want to Broadcast UDP packets out on a local network, what destination address do I use

You could use the limited broadcast address 255.255.255.255, however it is best to use the correct IP broadcast address of your local network segment (more successful in my own experience). You can calculate the correct broadcast address, see here.

/M

Home page

how to establish usb communication in MFC?

ashokbngr5-Sep-07 22:43

ashokbngr

5-Sep-07 22:43

Hi,

I need any sample..code or advice for usb communication in MFC.
I need to do read and write operations on a usb device.. Confused | :confused:

thanks in advance
Ashok

Re: how to establish usb communication in MFC?

Cedric Moonen5-Sep-07 23:16

Cedric Moonen

5-Sep-07 23:16

Which kind of device are you communicating with ? USB doesn't work like a serial port: you don't have access directly to the port but instead you get the handle of a driver. This driver is shipped with the device you want to communicate with and manages all the communication with the device.

To get the handle of the driver, simply call CreateFile supplying the correct driver name, then you should be able to use ReadFile and WriteFile. You can also do some more specific stuff by calling DeviceIOControl (in which you can pass some specific IO code which is dependent of your driver).

So, if you want more help, you'll need to give a lot more information (which device do you try to access, if you have documentation with it, ...).

Cédric Moonen
Software developer

Charting control [v1.2]

numerical methods

mitsui585-Sep-07 22:00

mitsui58

5-Sep-07 22:00

can anybody help me make a program that can do any of these numerical method?

moss,newton method, secant method, taylor-maclauren,bisection method,gaussian elimination, gauss-seindal,lagrange method.

thanks guys!! Big Grin | :-D

Re: numerical methods

Russell^'5-Sep-07 22:39

Russell^'

5-Sep-07 22:39

homework?

don't tell me that you don't find the way to implement the secant-method or bisection method! Big Grin | :-D

You have only to implement the algorithm:

ask for a function f(x) and for the borders x1 and x2.
check that sign(f(x1)) != sign(f(x2)) .
Then compute x3 inside the interval (x1, x2). This according on the algorithm, in bisection case x3=(x1+x2)/2,....in secant method it's only the point where the line from (x1,f(x1)) to (x2,f(x2)) intercept the x-axe.
then choose the new interval (or x1-x3 or x3-x2) according on where is the root.
Then start again on the new interval.
Do this 10000...000 times and stop it. Or stop when the interval is "too small".

That's it.
Smile | :)

Russell

Re: numerical methods

mitsui585-Sep-07 22:53

mitsui58

5-Sep-07 22:53

thanks russell!

it a project actually.. Smile | :)

Re: numerical methods

Russell^'5-Sep-07 23:13

Russell^'

5-Sep-07 23:13

ok, you convinced me.;)
Then you won this link[^].
Big Grin | :-D

(the routines are in C, not in C++. but it is easy to translate they)

Russell

Re: numerical methods

mitsui587-Sep-07 4:35

mitsui58

7-Sep-07 4:35

thanks for the link Smile | :)

that's really helpful.

Re: numerical methods

David Crow6-Sep-07 3:28

David Crow

6-Sep-07 3:28

mitsui58 wrote:
can anybody help me make a program that can do any of these numerical method?

Yes, I'm sure someone can.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: numerical methods

ollydbg239-Sep-07 1:05

ollydbg23

9-Sep-07 1:05

you can use the GNU scientific library.
It will give your the needed method.

How can I monitor the cts pin of serial port using dcb

yaminisridaran5-Sep-07 20:06

yaminisridaran

5-Sep-07 20:06

Can any one suggest me some ways to monitor the cts pin of the serial port using DCB.

S.Yamini

Re: How can I monitor the cts pin of serial port using dcb

chandu0045-Sep-07 20:26

chandu004

5-Sep-07 20:26

i have worked very enough with serial port(RS 232).
but never heard of the cts pin and dcb.
atleast for my information please educate me regarding those.
then i will try to solve if it in my perview.
thanku.

Re: How can I monitor the cts pin of serial port using dcb

yaminisridaran5-Sep-07 20:30

yaminisridaran

5-Sep-07 20:30

I am using vc++ 6.0 for serial port communication. dcb is structure defines the control setting for a serial communications device.
I have to monitor the cts (Clear to send)pin of the serial port.

S.Yamini

Re: How can I monitor the cts pin of serial port using dcb

chandu0045-Sep-07 20:51

chandu004

5-Sep-07 20:51

I use PCOMM library for sending and receiving data using serial port.
functions are like
sio_ioctl(); to define the port settings.
sio_read();
sio_write();
soi_iqueue();to find weather any data is there in the port.
may be i can help you if you are also using these libraries and functions.

Re: How can I monitor the cts pin of serial port using dcb

QuickDeveloper5-Sep-07 20:41

QuickDeveloper

5-Sep-07 20:41

yaminisridaran wrote:
Can any one suggest me some ways to monitor the cts pin of the serial port using DCB.

i think u need to set fOutxCtsFlow flag of the DCB to TRUE to monitor the CTS signal.

"Every morning I go through Forbes list of 40 richest people in the world. If my name is not in there, I go to work..!!!"

Re: How can I monitor the cts pin of serial port using dcb

yaminisridaran5-Sep-07 20:43

yaminisridaran

5-Sep-07 20:43

I have set fOutxCtsFlow to true but it is always true even if the voltage level in cts pin changes.

S.Yamini

Re: How can I monitor the cts pin of serial port using dcb

Cedric Moonen5-Sep-07 20:50

Cedric Moonen

5-Sep-07 20:50

Take a look at functions like GetCommModemStatus[^], WaitCommEvent[^] or GetCommMask[^]

Cédric Moonen
Software developer

Charting control [v1.2]

Re: How can I monitor the cts pin of serial port using dcb

yaminisridaran5-Sep-07 20:56

yaminisridaran

5-Sep-07 20:56

I already using GetCommState.

My Code
CString strPort;
strPort.Format("COM%d:",1);
m_hPort=CreateFile(strPort,GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
if(m_hPort==INVALID_HANDLE_VALUE)
{
return false;
}

GetCommState(m_hPort,&dcb);

BOOL res;
dcb.fOutxCtsFlow=true;
res=SetCommState(m_hPort,&dcb);
// Configure serial port
GetCommState(m_hPort,&dcb);

if(dcb.fOutxCtsFlow==TRUE)
TRACE("TURNED OFF");
else if(dcb.fOutxCtsFlow==FALSE)
{
TRACE("TURNED ON");
}
dcb.fOutxCtsFlow is always true even the voltage level changes

S.Yamini

Re: How can I monitor the cts pin of serial port using dcb

Cedric Moonen5-Sep-07 20:59

Cedric Moonen

5-Sep-07 20:59

Did you read my message ? Where do I speak about GetCommState ? I even gave you the link to the documentation, did you have a look at them ?

Cédric Moonen
Software developer

Charting control [v1.2]

Using MFC to access the internet

D_code_writer5-Sep-07 19:43

D_code_writer

5-Sep-07 19:43

Hey guys,

I develop applications using MFC and Visual C++ 6 and I am working on a particular application that needs to access data over the internet.

Can I do this using the MFC Framework or am I better just biting the bullet and get myself up to speed with Visual C# 2005?

Best Regards

Danny Nowlan

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