Tricky C++ question - C / C++ / MFC Discussion Boards

Suhail Yousaf29-Oct-03 23:32

29-Oct-03 23:32

I am using the AfxBeginThread, with a global function ThreadProc(LPVOID), i do some background processing ie a while loop is executing infinitely but due to that execution i have to update some controls on the Dialog.
This updation is not occurring rather an error message
comes that u can't modify a C++ class inside the thread
Please can someone tell me what is the problem and the solution...thanks

Ever Welcome...

Re: Threads ....

Anthony_Yio30-Oct-03 0:38

Anthony_Yio

30-Oct-03 0:38

You can pass in a parameter to a thread function.

CWinThread* AfxBeginThread( 
AFX_THREADPROC pfnThreadProc, 
LPVOID pParam, <-- the parameter
int nPriority = THREAD_PRIORITY_NORMAL, 
UINT nStackSize = 0, 
DWORD dwCreateFlags = 0, 
LPSECURITY_ATTRIBUTES lpSecurityAttrs = NULL );
CWinThread* AfxBeginThread( 
CRuntimeClass* pThreadClass, 
int nPriority = THREAD_PRIORITY_NORMAL, 
UINT nStackSize = 0, 
DWORD dwCreateFlags = 0, 
LPSECURITY_ATTRIBUTES lpSecurityAttrs = NULL );

Sonork 100.41263:Anthony_Yio

Re: Threads ....

vcplusplus30-Oct-03 2:57

vcplusplus

30-Oct-03 2:57

void CMyDlg::StartThread() 
{
    AfxBeginThread(MyThread, this, THREAD_PRIORITY_.....);
}

UINT MyThread(LPVOID pParam)
{
  CMyDlg *pMyDlg = (CMyDlg *)pParam;
		
  ...
  ...
  ...
  ...

}

Re: Threads ....

David Crow30-Oct-03 3:34

David Crow

30-Oct-03 3:34

It's hard to discern from your description, but if your secondary thread is trying to update a control owned by the primary thread, trouble is right around the corner. When an update is needed, the secondary thread should post a message to the primary thread indicating what needs to be done.

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Activating / Deactivating menus and toolbars

Florin Ochiana29-Oct-03 23:14

Florin Ochiana

29-Oct-03 23:14

Hi,

I have a program in which I have to activate / deactivate different menu options in different stages of the program.

How can I do this?

I also have to activate / deactivate a toolbar. I've managed to do this at startup by chaging the commands id's with SetButtonInfo. When I want to activate I use again SetButtonInfo to associate the right commands to the buttons and then the toolbar becomes active. If I try to change again the commands ids the toolbar doesn't deactivates again.

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

Network packets sniffer

Anonymous29-Oct-03 23:08

Anonymous

29-Oct-03 23:08

I have to develop an application that "sniffs" all UDP
packets sent over the LAN.
How can I develop this functionality ??
Are there some VC++ sample applications ??

Thanks a lot !!!

Re: Network packets sniffer

Joao Vaz29-Oct-03 23:41

Joao Vaz

29-Oct-03 23:41

See WinPcap[^]

Cheers,Joao Vaz
Three primary LAN architectures for Network Engineers,
under the sky,
Seven OSI layers for the Open System Architects,
in their halls of stone,
Nine N-xDU operations* for mortal Developers,
doomed to die,
One protocol suite for the Dark Sysadmin,
in his dark server room,
In the land of mordor.net,
where the shadowed fibers lie

Tricky C++ question

YaronNir29-Oct-03 22:57

YaronNir

29-Oct-03 22:57

Hi all,

I want to declare on a method that one of its parameter is a pointer to a function. the function is not the same for each call, meaning it can get different parameters each time..... i know i need to use the 3 dots to define the undetermined parameters....

touble is i am not familier with the syntax of either cases.....

can any1 help plz?

thanks in advanced

Yaron

Ask not what your application can do for you,
Ask what you can do for your application

Re: Tricky C++ question

Ian Darling29-Oct-03 23:10

Ian Darling

29-Oct-03 23:10

This sounds like a job for function objects.

What you do is define a class and implement a standard function that can be called (usually operator()). Then you can pass the parameters to an instance of your class in the constructor, pass the object to your method, and then call the standard function from within the method.

This article seems to be a reasonable pointer in the right direction:

http://www.informit.com/isapi/guide~cplusplus/seq_id~135/guide/content.asp[^]

HTH

--
Ian Darling
"The moral of the story is that with a contrived example, you can prove anything." - Joel Spolsky

Re: Tricky C++ question

YaronNir29-Oct-03 23:12

YaronNir

29-Oct-03 23:12

tons of thanks! Big Grin | :-D

cheers

Yaron

Ask not what your application can do for you,
Ask what you can do for your application

Re: Tricky C++ question

Juan Antonio Bermejo29-Oct-03 23:19

Juan Antonio Bermejo

29-Oct-03 23:19

Try something like...

typedef void (* TFunction)(int param1, ...);

void MyFunction(TFunction pF)
{
pF(90, 30, 20, 10);
};

Best regards
jAB

Re: Tricky C++ question

YaronNir29-Oct-03 23:23

YaronNir

29-Oct-03 23:23

thanks man,

that's really helpfull

cheers

Yaron

Ask not what your application can do for you,
Ask what you can do for your application

Re: Tricky C++ question

YaronNir29-Oct-03 23:26

YaronNir

29-Oct-03 23:26

an other question please...

what is the syntax for calling the MyFunction?? what do i pass as parameter for TFunction PF??? can u show me code

thanks

Yaron

Ask not what your application can do for you,
Ask what you can do for your application

Re: Tricky C++ question

Juan Antonio Bermejo29-Oct-03 23:32

Juan Antonio Bermejo

29-Oct-03 23:32

Here is the whole code...

typedef void (* TFunction)(int param1, ...);

void MyFunction(TFunction pF)
{
pF(90, 30, 20, 10);
};

void OtherFunction(int param1, ...)
{
// Do something
}

// Calling...
...
MyFunction(OtherFunction);
...

Re: Tricky C++ question

YaronNir29-Oct-03 23:38

YaronNir

29-Oct-03 23:38

thanks..

c code is a little misunderstood for me... i will describe the problem i have in c++ maybe you can write the proper example code :

the class CBDRMainDlg contains the called method :

class CBDRMainDlg
{
public
.
.
void ClearIt(); // the method that will be called
};

the class also contains a function called add that one of its parameters is a pointer to the method ClearIt:

class CBDRMainDlg
{
public
  void Add( // here should be the declaration of the pointer to a function);
.
.
void ClearIt(); // the method that will be called
};

out side the class in on other class i am defining an object of the class:

...
...
CBDRMainDlg dlg;
// here is where i want to call the add function with the pointer to 
// ClearIt as the first parameter

dlg.DoModal();

see all the remarks above, can u replace them with the proper code?

thanks again for all your help

Cheers
Yaron

Ask not what your application can do for you,
Ask what you can do for your application

Re: Tricky C++ question

Juan Antonio Bermejo30-Oct-03 21:21

Juan Antonio Bermejo

30-Oct-03 21:21

This is sintactically correct:

class CBDRMainDlg;

typedef void (CBDRMainDlg::* DlgMethod)(void);

class CBDRMainDlg
{

public:
void Add(DlgMethod method)
{

};
void ClearIt()
{
printf("Clear It");
};
};

int main(int argc, char* argv[])
{
CBDRMainDlg dlg;

dlg.Add(CBDRMainDlg::ClearIt);

return 0;
}

... but i can't figure out how to call the method inside 'Add' since the compiler needs to push the this pointer in the stack before make the calling. It is possible using inline asm but i think that is not the best solution...

Why do you want to call methods this way? I think you can do that using virtual methods...

SysIPAddress32 in VC++ 5.0

Phil.Benson29-Oct-03 22:44

Phil.Benson

29-Oct-03 22:44

I have a problem, I´m trying to use the IP address control in a VC++ 5.0 project. The code should be ok, but, when the resources are to be compiled, it does not recognise the SysIPAddress32 control.

Does anybody have a solution for this, i.e. do I have to set the control (in the resource editor) as a custom control, and if yes, how?

Thanks in advance

Phil

bum... and I thought I´d got rid of all the bugs Frown | :(

Re: SysIPAddress32 in VC++ 5.0

saarfu15-Dec-09 4:51

saarfu

15-Dec-09 4:51

HI,
are you able tyo create CIPAddressCtrl

and use ??
please help me if you can
thanks
sarfu

Re: SysIPAddress32 in VC++ 5.0

Phil.Benson15-Dec-09 5:26

Phil.Benson

15-Dec-09 5:26

Sorry, but if you look at the date, this is over 6 years ago, and for the life of me I can't remember how I got it to work... I've moved onto "Greener Pastures" now Wink | ;-)

Cheers
Phil

Who the f*** is General Failure, and why is he reading my harddisk?

IHTMLDOMNode appendChild return E_INVALIDARG

ShayAmar29-Oct-03 21:50

ShayAmar

29-Oct-03 21:50

Hi,

I need some help please.
I tried to figure it out, but with no success so far.
Why do I get E_INVALIDARG when I try to use the appendChild Function.
This is my source code:

IHTMLElement* pHTMLElement;
IHTMLElement* pNewHTMLElement;
IHTMLDOMNode* pHTMLDOMNode;
IHTMLDOMNode* pNewHTMLDOMNode;
IHTMLDOMNode* pNew2HTMLDOMNode;
IDispatch* pDisp;

v.vt = VT_BSTR;
v.bstrVal = SysAllocString(L"HEAD");

hResult = pIHTMLElementCollection->tags(v,&pDisp );

if (hResult == S_OK)

{
hResult = pDisp->QueryInterface(IID_IHTMLElementCollection,(void**)&pIHTMLElementCollection);
if (hResult == S_OK)
{
pIHTMLElementCollection->get_length(&lCollectionSize);

v.vt = VT_I4;
v.lVal = 0;

hResult = pIHTMLElementCollection->item(v,v,&pDisp);

if (hResult == S_OK && pDisp != NULL)
{
hResult = pDisp->QueryInterface(IID_IHTMLElement,(void**)&pHTMLElement);
if (hResult == S_OK)
{
hResult = pHTMLElement->QueryInterfa(IID_IHTMLDOMNode,(void**)&pHTMLDOMNode);

if (hResult == S_OK)
{
bstrTemp = SysAllocString(L"BASE");
hResult = pIHTMLDocument2->createElement(bstrTemp, &pNewHTMLElement);
SysFreeString(bstrTemp);

if (hResult == S_OK)
{
bstrTemp = SysAllocString(L"href");
v.vt = VT_BSTR;
v.bstrVal = strWebPageDomain.GetBuffer();

hResult = pNewHTMLElement->setAttribute(bstrTemp, v, 0);

SysFreeString(bstrTemp);

if (hResult == S_OK)
{
hResult = pNewHTMLElement->QueryInterface(IID_IHTMLDOMNode,(void**)&pNewHTMLDOMNode);
if (hResult == S_OK)
{

****************************************************************************
hResult = pHTMLDOMNode->appendChild(pNewHTMLDOMNode, &pNew2HTMLDOMNode);

****************************************************************************
}
}

}
}
}
}
}
}
}
}

Add Attachment with Outlook2000 Automation

NaturalBornChilla29-Oct-03 21:08

NaturalBornChilla

29-Oct-03 21:08

Good morning,
I have a problem with adding an file to a mail.
This process should use OLE Automation. I already figured out all the other things, but I'm not able to do that...
I also found no help in the msdn library, so you out there are my last chance...

Thanks in advance.

Manipulating File Open/Save Filters

Sreeramachandra29-Oct-03 20:34

Sreeramachandra

29-Oct-03 20:34

Hi there,

I have created a MDI Application which has two view(one derived from CEditView and other with CView) and get the data from one Document. No my problem is that i have used the method for Open/Save Filters using the article in this site and when i open the txt it is opening CEditView but the problem is that it is not opening the contents in the file. How to solve this problem if anybody knows plz reply me fast.

Sreeramachandra G

finding the IOCTRL for a Driver

Fad B29-Oct-03 20:14

Fad B

29-Oct-03 20:14

Hi Any one can help me in finding the IOCTRL for a Driver for a special Hardware. because I need to communicate with the driver in Kernel Mode not in user mode , and this Hardware have an interface via dll and the dll connect to the driver
Thanks for any help
Fadi

Rose | [Rose]

Re: finding the IOCTRL for a Driver

Alexander ^M.,30-Oct-03 2:37

Alexander ^M.,

30-Oct-03 2:37

oh, hi fadi Wink | ;)

there are some types of IOCTLs, the standard ones and the custom ones.
to find out the standard ones, read the DDK and/or the DDK header files.
the custom ones are a problem...

good luck,
alex

Don't try it, just do it! Wink | ;-)

Can anyone spot my mistake?

georgiek5029-Oct-03 19:06

georgiek50

29-Oct-03 19:06

<br />
szBuffer[0] = '\0';<br />
<br />
strncpy(szBuffer, cMediaFileInfo.szFrameRate, strlen(cMediaFileInfo.szFrameRate) - 4);<br />
<br />
// szFrameRate is "25.000 fps" (without quotes)<br />
				<br />
szBuffer[strlen(cMediaFileInfo.szFrameRate) - 4] = '\0';<br />
double dFramerate = atof(szBuffer);<br />

dFramerate is always 0.

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