Name Pipe Error - C / C++ / MFC Discussion Boards

Re: Edit control: only works once

Anonymous7-Jan-03 10:30

Anonymous

7-Jan-03 10:30

Thanks Alvaro, I'll look into this tomorrow when I'm back at work.

Thanks!

OnIdle function eats up 100% of the processor

Florin Ochiana30-Dec-02 10:52

Florin Ochiana

30-Dec-02 10:52

Hi! I have problems with onidle methods that take up 100% of the processor. If I overload the OnIdle method in the main class of my application, without anything in it:

BOOL CtestApp::OnIdle(LONG lCount) {
return TRUE;
}

than after the application starts it eats all the processor. In Windows task manager the CPU Usage is 100%. But if I start using the application (click through the menu, etc) the CPU Usage drops to 10-20 or even lower.
What can I do? I removed the OnIdle method from the main class but I need an OnIdle method in a socket class to receive the messeges as they arrive from the server.

The OnIdle method is started like this: AfxBeginThread(OnIdle2,0);
and it looks like this

UINT OnIdle2(LPVOID pParam) {
int z;
DWORD dwWaitResult;
sockArray[0] = globalSocketHandler;
int wMsg = 190190;
while (OnIdleContinue) {
dwWaitResult = WaitForMultipleObjects(1,sockArray,TRUE,10);
z = WSAAsyncSelect(theApp.socket.GetSock(),AfxGetApp()->GetMainWnd()->GetSafeHwnd(),wMsg,FD_READ);
switch (dwWaitResult) {
case WAIT_OBJECT_0:
//read
strcpy(theApp.socket.buff,"");
theApp.socket.ReadMsg();
break;
default:
TRACE("nothing\n");
//nothing;
break;
}
}
return 1;
}

Thank you for any suggestion.

-----
We are what we repeatedly do. Excellence, then, is not an act, but a habit.

Re: OnIdle function eats up 100% of the processor

pba_30-Dec-02 11:08

pba_

30-Dec-02 11:08

If you return a non-zero value from OnIdle you are asking for more idle processing time ( and you will get it ).Return 0 if you don't need more.

Re: OnIdle function eats up 100% of the processor

Paul Oss30-Dec-02 19:35

Paul Oss

30-Dec-02 19:35

This is a bit of a long subject but you might consider listening to your socket in a seperate thread instead of using the OnIdle override. Functionally, it's probably easier to manage using the onidle, but I think a multithreaded solution would give you much more flexibility.

Paul

Re: OnIdle function eats up 100% of the processor

Anonymous31-Dec-02 1:35

Anonymous

31-Dec-02 1:35

My OnIdle function it was actually a separate thread, not an override of the OnIdle function. Smile | :)

I fixed the problem. It seems that the function waitformultipleobjects did this.

Now my function does just a repetead read on the socket and if there is a message than it processes it.

Thanks for the help.

A Happy New Year!

Florin

semaphores and threads

amica30-Dec-02 10:48

amica

30-Dec-02 10:48

I'm trying to simulate a multiprocess job with the use of semaphores, but I'm not fluent in C++. Anybody knows how to implement such thread controls?

Re: semaphores and threads

pba_30-Dec-02 11:17

pba_

30-Dec-02 11:17

The C++ standard does not cover multithreading. If you want to implement multithreaded apps you will have to use platform specific routines - for windows look in MSDN for synchronization functions ( InitializeCriticalSection, CreateMutex, CreateSemaphore, etc). One of the best samples of how to use them is MFC - look in the implementation of CMutex , CSemaphore, and the rest of synchronization classes.

Name Pipe Error

Spiros30-Dec-02 10:08

Spiros

30-Dec-02 10:08

I am writting a windows application that uses Namepipes for IPC. I have a strange problem which is that this IPC some times fails in a random way. It will work just fine for some time and then suddenly will thow an exception saying that the namepipe initiator is expecting for the other end to open the pipe. The main issue is that this behavior is random and so far there is no way to repeat the error when I want it. I would appreciate any ideas for handling this issue. Thank you in advance for your time.

Spiros Prantalos
Miami the place to be!!

CButton text at run time

jimNLX30-Dec-02 9:07

jimNLX

30-Dec-02 9:07

I'm trying to set the button text on the fly so that it can change labels as things change in my app.

I have been unable to figure out how/what type of var will work.

I've tried an array of char, a pointer, but it seem to only work when I use "blah....".

Is there a way? Maybe I just need some more coffee Smile | :)

Re: CButton text at run time

jimNLX30-Dec-02 9:35

jimNLX

30-Dec-02 9:35

DOUGH! I got it...seems in my attempt at this I left the button definition where it was...later in the program!

That coffee really works!

Thanks for looking

Re: CButton text at run time

Thomas Lau30-Dec-02 18:19

Thomas Lau

30-Dec-02 18:19

SetDlgItemText(....)
try. Smile | :)

How do I get process name from handle?

Neil scsn30-Dec-02 8:30

Neil scsn

30-Dec-02 8:30

hi,
I am using a system wide hook and get the handle (HWND) of the process about to start. How do I get the filename from this handle?

i am running win98,nt,2000,xp

thanks

neil

Re: How do I get process name from handle?

pba_30-Dec-02 11:03

pba_

30-Dec-02 11:03

If you have the window handle you can use GetWindowThreadProcessId to get the process id , then using PSAPI or ToolHelp lib you can get the file name.

Is this possible....

Member 9630-Dec-02 7:56

Member 96

30-Dec-02 7:56

I have vc++ .net and I have a project that has a single define for compiling certain code for U.S. users and other code for Canadian users.

What I want to do is build two releases at the same time from the same code with one being built with the define BUILDCANADA defined and the other not, but I don't want to have two separate projects.

I see lot's of info on doing simultaneous separate builds based on compiler settings etc, but nothing that shows if it's possible to do one build with a define set and another with it not set. I guess what the real question is, is can you set a DEFINE in the build options somewhere?

Re: Is this possible....

Anders Molin30-Dec-02 9:44

Anders Molin

30-Dec-02 9:44

Go into the "Build" menu, click on "Configuration Manager", here you can make multible configurations.

Then you can go into th projects options, and define what you need for each configuration.

To build both projects in a single step, select "Batch Build..." in the "build" menu...

- Anders

Money talks, but all mine ever says is "Goodbye!"

Re: Is this possible....

Member 9630-Dec-02 11:05

Member 96

30-Dec-02 11:05

Hi Anders, thanks for replying. I know you can do that, but the critical thing is that I need to have a DEFINE set differently for the two builds, is that possible?

Re: Is this possible....

peter271330-Dec-02 12:43

peter2713

30-Dec-02 12:43

In "Configuration dialog|C/C++|Preproccesor", there is an option called "Preprocessor definitions" where you can define your BUILDCANADA or whatever you want.

--------
Dave

Re: Is this possible....

Member 9630-Dec-02 15:35

Member 96

30-Dec-02 15:35

Perfect! Exactly what I was trying to find.

Thank you very much.

Function required similar to DOS "deltree.exe"

Still learning how to code30-Dec-02 7:45

Still learning how to code

30-Dec-02 7:45

Hi, In my program (VC++, MFC, MDI ap), I need a function to delete a directory and all it's contained files and sub-directories. I'm currently using "system" to call the DOS program Deltree.exe. However, I'm sure that there should be a pure Windows method to do the same thing that would be much cleaner. Has anyone any suggestions ?

Doug

Re: Function required similar to DOS "deltree.exe"

Jason Henderson30-Dec-02 8:30

Jason Henderson

30-Dec-02 8:30

Try this:

BOOL DelTree(CString cstrPath)
{
	BOOL bRetVal = FALSE;
	CString cstrTemp = cstrPath;
	CString cstrOldDir;
	char buffer[MAX_PATH];
	
	CFileFind cFind;
	CString cstrFileName, cstrTempFile;

	cstrFileName.Format("%s%s",cstrPath,"\\*.*");
	if (cFind.FindFile(cstrFileName))
	{	
		BOOL bFound = TRUE;
		while (bFound)
		{
			bFound = cFind.FindNextFile();
			if (cFind.IsDots())
				continue;
			else
			{
				// Get Current File Name
				cstrTempFile = cFind.GetFilePath();
				bRetVal = DeleteFile(cstrTempFile);
				if (!bRetVal) break;
			}
		}
	}
	cFind.Close();
	
	if (bRetVal)
		bRetVal = ::RemoveDirectory(cstrPath);
	else
		// put a failure message here

	return bRetVal;
}

Jason Henderson
^{start page ; articles}
_{henderson is coming}
^{henderson is an opponent's worst nightmare}
^{* googlism *}

Re: Function required similar to DOS "deltree.exe"

Alvaro Mendez30-Dec-02 10:06

Alvaro Mendez

30-Dec-02 10:06

Jason,

Your solution appears correct. However, I'd like to point out a small detail which caught my eye. Your function's signature is BOOL DelTree(CString cstrPath). Your parameter is a CString value, rather than a constant CString reference, which would be more appropriate: BOOL DelTree(const CString& cstrPath).

I just wanted to point this out to you and hope that you understand why it's usually much better to pass objects by const reference rather than by value. I realize that the CString class has a copy-on-write scheme which makes passing by value a lot less expensive than it otherwise be. But, passing by const reference is still the most efficient way to pass most objects requiring "by-value" semantics.

Regards,
Alvaro

Well done is better than well said. -- Benjamin Franklin
(I actually prefer medium-well.)

Re: Function required similar to DOS "deltree.exe"

Jason Henderson30-Dec-02 10:15

Jason Henderson

30-Dec-02 10:15

Thanks.

Actually, I took this code from a COM dll and modified it rather quickly. I really didn't look it over all that well.

Jason Henderson
^{start page ; articles}
_{henderson is coming}
^{henderson is an opponent's worst nightmare}
^{* googlism *}

Re: Function required similar to DOS "deltree.exe"

Ancient Dragon31-Dec-02 2:00

Ancient Dragon

31-Dec-02 2:00

The only problem I see is that it is not recursive, so it will not work like deltree, deleting all sub-directories and their contents too.

Re: Function required similar to DOS "deltree.exe"

Jason Henderson31-Dec-02 2:44

Jason Henderson

31-Dec-02 2:44

Hey you're right. Good catch.

It would be easy to modify though.

Jason Henderson
^{start page ; articles}
_{henderson is coming}
^{henderson is an opponent's worst nightmare}
^{* googlism *}

Re: Function required similar to DOS "deltree.exe"

Alvaro Mendez30-Dec-02 9:50

Alvaro Mendez

30-Dec-02 9:50

Jason gave you the clean solution. However, here's another one similar to your "system" one, except that it doesn't show the DOS window:

::WinExec("deltree blah", SW_HIDE);

Regards,
Alvaro

Well done is better than well said. -- Benjamin Franklin
(I actually prefer medium-well.)

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