C / C++ / MFC Discussion Boards

Re: Best way to measure time interval of external events

Code-o-mat25-Mar-09 5:56

Code-o-mat

25-Mar-09 5:56

Good point.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

Re: Best way to measure time interval of external events

Joe Woodbury25-Mar-09 6:47

Joe Woodbury

25-Mar-09 6:47

If the external event uses an interrupt on the PC, the scheduler is irrelevant.

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: Best way to measure time interval of external events

CPallini25-Mar-09 7:02

CPallini

25-Mar-09 7:02

And how does the interrupt awake your user space thread?
Smile | :)

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Re: Best way to measure time interval of external events

Joe Woodbury25-Mar-09 7:07

Joe Woodbury

25-Mar-09 7:07

You retrieve the CPU performance counter in the ISR and write the time to file or through a shared memory queue or something of the like.

It should also be pointed out that waking a thread is usually done on less than a thread quanta. However, without a real-time kernel extension, even if your thread is highest priority, this signaling is not deterministic. But, as I said, if you store the actually counters in the ISR, this isn't an issue.

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: Best way to measure time interval of external events

CPallini25-Mar-09 7:34

CPallini

25-Mar-09 7:34

So you've to write some kernel mode code or am I wrong?

Re: Best way to measure time interval of external events

Joe Woodbury25-Mar-09 7:43

Joe Woodbury

25-Mar-09 7:43

Yes.

Or you get a real-time extension for XP (like RTX from http://www.intervalzero.com/[^])

(I've never needed this degree of precision in XP, but if I did, I'd be inclined to use a micro-controller and something like eCOS on it to do the timings and then send the results to XP via serial port.)

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: Best way to measure time interval of external events

CPallini25-Mar-09 7:52

CPallini

25-Mar-09 7:52

Joe Woodbury wrote:
I've never needed this degree of precision in XP, but if I did, I'd be inclined to use a micro-controller

The same I would do.

Thank you for enlightening.
Smile | :)

Re: Best way to measure time interval of external events

Jonathan Davies25-Mar-09 7:06

Jonathan Davies

25-Mar-09 7:06

Get an IO card which provides events or callbacks via a library when a given input changes state. One I used called NextMove (overkill for your needs) had the first 3 or 4 inputs using interrupts. Try Amplicon (I think) or similar for an IO card.

MAC adresss code error

optical12325-Mar-09 3:42

optical123

25-Mar-09 3:42

Dear All

// Fetches the MAC address and prints it
static void GetMACaddress(void)
{
IP_ADAPTER_INFO AdapterInfo[16]; // Allocate information
// for up to 16 NICs
DWORD dwBufLen = sizeof(AdapterInfo); // Save memory size of buffer

DWORD dwStatus = GetAdaptersInfo( // Call GetAdapterInfo
AdapterInfo, // [out] buffer to receive data
&dwBufLen); // [in] size of receive data buffer
assert(dwStatus == ERROR_SUCCESS); // Verify return value is
// valid, no buffer overflow

PIP_ADAPTER_INFO pAdapterInfo = AdapterInfo; // Contains pointer to
// current adapter info
do {
PrintMACaddress(pAdapterInfo->Address); // Print MAC address
pAdapterInfo = pAdapterInfo->Next; // Progress through
// linked list
}
while(pAdapterInfo); // Terminate if last adapter
}

can anybody just walk through my code and here i am staticaly allocting the memory for the storing the adpater information for upto 16 NIC card...
but if i want to get and enumerate all the MAC addresses on my PC...
the above code will give upto 16 card so what to do next...

plz help me....

Regards
sunny

Re: MAC adresss code error

Electron Shepherd25-Mar-09 4:40

Electron Shepherd

25-Mar-09 4:40

I think you've misunderstood how the function works. It doesn't populate an array, but a linked list. See http://msdn.microsoft.com/en-us/library/aa365917(VS.85).aspx[^].

Server and Network Monitoring

Re: MAC adresss code error

optical12325-Mar-09 5:05

optical123

25-Mar-09 5:05

Hey

ya it will generate link list...but my problem is how to allocate memory if more than 16 cards in the system.......

Regards
Sunny

Re: MAC adresss code error

Electron Shepherd25-Mar-09 7:06

Electron Shepherd

25-Mar-09 7:06

Don't hard code the 16. From the link I gave you:

pOutBufLen [in, out]
A pointer to a ULONG variable that specifies the size of the buffer pointed to by the pAdapterInfo parameter. If this size is insufficient to hold the adapter information, GetAdaptersInfo fills in this variable with the required size, and returns an error code of ERROR_BUFFER_OVERFLOW.

Take a look at the sample code in the link and see how they do it.

Server and Network Monitoring

How to Display Radio button dynamically on Dialog.

hemlat25-Mar-09 3:39

hemlat

25-Mar-09 3:39

Hi,
I have written following code in my MFC code to display Radio Button on my dialog.

CButton myButton;
myButton.Create(_T("My button"), WS_CHILD|WS_VISIBLE|BS_RADIOBUTTON, 
   CRect(50,40,80,70),this, 1);

But Dialog is not showing Radio button.Can anyone help me.

Re: How to Display Radio button dynamically on Dialog.

led mike25-Mar-09 4:37

led mike

25-Mar-09 4:37

There are a number of things that could be the reason. Definitively know from your post we cannot.

My advice is that you learn how rendering is done in Windows OS which will enable you to determine your specific problem.

Re: How to Display Radio button dynamically on Dialog.

Electron Shepherd25-Mar-09 4:45

Electron Shepherd

25-Mar-09 4:45

What function is this code in? My guess would be that myButton is going out of scope and being destroyed just after it's been created.

Server and Network Monitoring

Re: How to Display Radio button dynamically on Dialog. [modified]

hemlat25-Mar-09 18:08

hemlat

25-Mar-09 18:08

Thanks for your reply.Previously myButton is local variable in OnInitDialog function. I have changed it to member variable and I have allocated memory.It is working fine and it is displaying Radio Button.

I have changed this to Push Button. I need to add Event Handler to this Button.Can any one help me.

modified on Thursday, March 26, 2009 12:17 AM

Re: How to Display Radio button dynamically on Dialog.

mutpan4-Feb-10 5:46

mutpan

4-Feb-10 5:46

you need to derive the new class from CButton and add the event handler in that class

I/O operation sytem error

LCI25-Mar-09 3:33

LCI

25-Mar-09 3:33

I am in a loop, reading from an RS232 port. There are times when i receive an exception with a system message that says:
"The I/O operation has been aborted because of either a thread exit or an application request"

// read a byte from port
while (!m_bExit)
{

// reset flag variables
dwBytesRead = 0;

// read
bRC = ReadFile(m_hCommPort, pDataBuff, 20, &dwBytesRead, NULL);
dwError = GetLastError();

if (!bRC)
{
if (ERROR_HANDLE_EOF != dwError || ERROR_TIMEOUT != dwError)
{
LPVOID SysMsg;

// reterieve system message
FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
NULL,
dwError,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR)&SysMsg,
0,
NULL );

// show system message
ZeroMemory( m_szBuffer, sizeof(m_szBuffer) );
wsprintf(m_szBuffer, TEXT("ReadRS232Data() over %s: ReadFile(), %s"), m_Port, (LPCTSTR)SysMsg);

LocalFree(SysMsg);
return 0;
}
}

Has anyone ever found a solution to this or know what would cause this error? Cause once this happens you cannot read from the port until it is out of this conditions which seems to just happen on its own.

Thanks in advance for any help or direction.

Re: I/O operation sytem error

led mike25-Mar-09 4:33

led mike

25-Mar-09 4:33

LCI wrote:
I am in a loop

That sounds uncomfortable.

LCI wrote:
or know what would cause this error

What is the number returned from GetLastError?

Re: I/O operation sytem error

Cedric Moonen25-Mar-09 4:40

Cedric Moonen

25-Mar-09 4:40

led mike wrote:
That sounds uncomfortable.

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

Re: I/O operation sytem error

LCI25-Mar-09 5:37

LCI

25-Mar-09 5:37

I do not log the number that returns, but the related message is :

"The I/O operation has been aborted either because of a thread exit or an application request."

BTW, i cannot reproduce. I just know when it happens.

Catch(exception)

NewVC++25-Mar-09 2:39

NewVC++

25-Mar-09 2:39

Hi All

How can i Use AfxmessBox through Catch(exception)?Plz help me

i have code like this

try{
//Something here
}
catch(exception er)
{
AfxmessBox(er)
}

Plz help me

Re: Catch(exception)

Cedric Moonen25-Mar-09 2:41

Cedric Moonen

25-Mar-09 2:41

By calling exception::what() maybe ?

try
{
  //Something here
}
catch(exception er)
{
  AfxmessBox(er.what());
}

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

Re: Catch(exception)

Yusuf25-Mar-09 3:12

Yusuf

25-Mar-09 3:12

Cedric Moonen wrote:
try{ //Something here}catch(exception er){ AfxmessBox(er.what());}

plz hlp. i m getting err.

ERROR - 404 - Undefined Method 'AfxmessBox' - txtpsk detected!!!!!!

what is next, kidz coding in txtspk Roll eyes | :rolleyes:

Yusuf

Oh didn't you notice, analogous to square roots, they recently introduced rectangular, circular, and diamond roots to determine the size of the corresponding shapes when given the area. Luc Pattyn[^]

Re: Catch(exception)

ThatsAlok25-Mar-09 17:43

ThatsAlok

25-Mar-09 17:43

Cedric Moonen wrote:
AfxmessBox(er.what());

New Api i think Smile | :)

... I think this must be AfxMessageBox()

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