C / C++ / MFC

24-Jun-03 0:54

I'm developing a Win32 console app in VC++ 6.0 where I have coded a edit box which works fine... however running my console app on Windows 98, my app affects the speed of the computer.

I have tracked the problem down to my "main input loop" where my app wait for the user to press a key.
The main loop (very simple!) looks something like this :

BOOL bOK=TRUE;
int cKey;
while (bOK)
{
    // Wait for keystroke...
    while (!_kbhit())
    {
      // Do nothing...
    }    

    // Getting the key...
    cKey = _getch();

    // Process the key here...
    // and so on and so on...
}

So my question is : is there a "proper" way to wait for a input chars in a console app which does not slow down Windows 9x ?

Please help, thanks Smile | :)

Rage24-Jun-03 1:13

Rage

24-Jun-03 1:13

I am not sure about what you mean with Win32 console app. Is it a Win32 application, or a console app ?

If you have the Win32 code, then just process the message loop and check for keyboard messages.

If not, I guess you can use getchar();.

~RaGE();

MrBean24-Jun-03 1:22

24-Jun-03 1:22

As i wrote... It's a Win32 console app Smile | :)

Not a DOS app but a 32bit console application.

Edit : I tried to process the Windopw messages but since my console app does not have a Windows (HWND) handle, I can't do that ;(

Peter Weyzen24-Jun-03 10:52

Peter Weyzen

24-Jun-03 10:52

Do the sleep() call. I have console-app based servers -- we do the same thing of a kbhit/getch loop to look for the shutdown keystroke.

With a sleep(100) this thread bears no impact on the process.... Thread priority is not a good way to do this, since the crux of the problem is that your thread is always awake and always processing.

Threads should not be wasting process time when they don't need to.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
Peter Weyzen<br />
Staff Engineer<br />
Santa Cruz Networks

MrBean24-Jun-03 22:59

24-Jun-03 22:59

I used the Sleep method which worked !

Thanks guys Smile | :)

Michael P Butler24-Jun-03 3:50

Michael P Butler

24-Jun-03 3:50

It has been a while since I've done anything like this but,

I don't think you need your _kbhit loop. _getch() will wait for a character to be pressed before executing the next statement.

This is the MSDN example

// crt_getch.c
// compile with: /c
/* This program reads characters from
 * the keyboard until it receives a 'Y' or 'y'.
 */

   int ch;

   _cputs( "Type 'Y' when finished typing keys: " );
   do
   {
      ch = _getch();
      ch = toupper( ch );
   } while( ch != 'Y' );

   _putch( ch );
   _putch( '\r' );    /* Carriage return */
   _putch( '\n' );    /* Line feed       */
}

Michael

'War is at best barbarism...Its glory is all moonshine. It is only those who have neither fired a shot nor heard the shrieks and groans of the wounded who cry aloud for blood, more vengeance, more desolation. War is hell.' - General William Sherman, 1879

MrBean24-Jun-03 3:55

24-Jun-03 3:55

Thanks... that seems to do the trick Smile | :)

However I need to do some processing in my _kbhit loop, but maybe I can find a workaround for this.

nfactorial24-Jun-03 5:36

nfactorial

24-Jun-03 5:36

If you need to do some processing inside the loop, call Sleep( 1 ) at the end of each loop. That should prevent starving windows of cpu time.

n!

MrBean24-Jun-03 22:56

24-Jun-03 22:56

Thanks, the Sleep worked for me Smile | :)

David Crow24-Jun-03 3:58

David Crow

24-Jun-03 3:58

I think _getch() has a built-in wait so you might try removing the call to _kbhit().

MrBean24-Jun-03 22:57

24-Jun-03 22:57

I needed some processing in the _kbhit loop but using Sleep in the loop solved the problem, thanks Smile | :)

peterchen24-Jun-03 9:35

peterchen

24-Jun-03 9:35

a) you can lower the thread priority while you wait for input
b) a Sleep(20) won't hurt

c) you can *try* if MsgWaitForMultipleObjects "wakes" your thread when you input a kjey (I doubt that, though)

"Der Geist des Kriegers ist erwacht / Ich hab die Macht" StS

sighist | Agile Programming | doxygen

MrBean24-Jun-03 22:56

ISO-8601 Date Format and COleDateTime

24-Jun-03 22:56

Thanks

I simply added a Sleep which did the trick Smile | :)

Braulio Dez24-Jun-03 0:40

Braulio Dez

24-Jun-03 0:40

Hi,

Is there any method, function or way... to convert from ISO-8601 Date Format (yyyy-mm-ddThh:mm:ss), to COleDateTime ?

I'm tempted to make my own sh*tty function... but reinventing the wheel it's not a good idea... ( at least reinvent a bad wheel Smile | :)

).

Thanks in advance, Greetings
Braulio

Re: ISO-8601 Date Format and COleDateTime

Rage24-Jun-03 1:09

Rage

24-Jun-03 1:09

BOOL ParseDateTime( LPCTSTR lpszDate, DWORD dwFlags = 0, LCID lcid = LANG_USER_DEFAULT );
throw( CMemoryException );
throw( COleException );

should do the job (see MSDN for more). This parses your string and sets the COleDateTime.

~RaGE();

C# DLL and MFC app

vikramlinux24-Jun-03 0:30

vikramlinux

24-Jun-03 0:30

Dear all,
How to access a C# DLL function from a MFC app? Is it possible?

VikramS

Kannan Kalyanaraman24-Jun-03 1:13

Kannan Kalyanaraman

24-Jun-03 1:13

Yes it is possible.
You can do this in two ways.

1. By adding the /CLR compiler option and after that you can use the "#using" keyword to get your dll into MFC. for ex. #using <mycsharpassembly.dll>
You can instantiate the class or type inside your c# dll and call the methods.
Also note that with this your application now compiles to IL instead of x86 code,so unless you intend to compile the entire app to .net, this is not required.

2. Through COM Interop.
By decorating the c# class with COM attributes(mostly GUID) and then using the regasm tool to register the C# dll. Now you got a proper COM component in .net and you can use this MFC like how you access normal COM components.

Cheers,
Kannan

vikramlinux24-Jun-03 1:31

vikramlinux

24-Jun-03 1:31

Ya.. I got it..that is really nice soln. Now I want to pass a safearray of strings to that C# DLL. how to do this? Frown | :(

Kannan Kalyanaraman24-Jun-03 1:52

Kannan Kalyanaraman

24-Jun-03 1:52

I think you need to change your mail id for the ms programs to work Smile | :)

, okay just kidding.
I have never tried this, but start looking into
MarshalAsAttribute.SafeArraySubType or UnmanagedType.SafeArray
as function parameters in c#

Cheers,
Kannan

vikramlinux24-Jun-03 1:56

vikramlinux

24-Jun-03 1:56

Thank you..MarshalAsAttribute.SafeArraySubType works nicely.Anyway I love linux and windows both Smile | :)

Vikram