Re: Constructing a parser - C / C++ / MFC Discussion Boards

Aqueel10-Jun-05 0:51

10-Jun-05 0:51

Hello
I am working with MultiThreading in MFC. I have written following piece in my code. But there is an error. Can anyone tell me why this error is comming.

Code is...

void CMyThreadrDlg::OnCreateThread()
{
if (m_check) // if check box is checked
{
int *i = new int(10000);
CWinThread *pThread = AfxBeginThread(getTime, i);
}
}

UINT CMyThreadDlg::getTime(LPVOID param)
{
DWORD result =0 ;

MessageBox("Thread created", "Success");

AfxEndThread(0);
return result;

}

Error is there where I have wrote,
CWinThread *pThread = AfxBeginThread(getTime, i);

Error Message is...

none of the 3 overloads can convert parameter 1 from type 'unsigned int (void *)'
Please help me

Thanks
Aqueel A. Mirza

We Believe in Excellence

Re: Question about MultiThreading

Cedric Moonen10-Jun-05 1:04

Cedric Moonen

10-Jun-05 1:04

The problem is that you pass to AfxBeginThread a member function of a class. This won't work because a member function does't not have the same calling convention as a standard function (the this pointer is passed implicitely).

Thus you need to use a global function. If your thread needs to access some member variables of the class that started the thread, you can pass the pointer to the class in the parameter:

UINT getTime(LPVOID param)<br />
{<br />
CMyThreadDlg* pDlg = (CMyThreadDlg*)param;<br />
<br />
//Do things with pDlg...<br />
<br />
//Don't need to call AfxEndThread because the thread will finish automatically when this function returns<br />
return 0;<br />
}<br />

And to spawn the thread:

void CMyThreadrDlg::OnCreateThread() <br />
{<br />
if (m_check) // if check box is checked<br />
{<br />
CWinThread *pThread = AfxBeginThread(getTime, this);  // pass the this pointer in the argument<br />
}<br />
}<br />

Also, you don't need to call AfxEndThread before leaving the thread function because the thread will automatically finishes when this function exits.

Re: Question about MultiThreading

Stlan10-Jun-05 1:14

Stlan

10-Jun-05 1:14

But if you want absolutely that the thread procedure be a member of the class, there is a simple solution: declare the thread procedure as static function member and pass this pointer as parameter to the thread, so that you are able to call a non-static member function of the class as true thread procedure.

class A<br />
{<br />
  public:<br />
  VOID StartThread();<br />
<br />
  private:<br />
  static LRESULT ThreadProc(LPVOID pParam);<br />
  VOID DoThread();<br />
}<br />
<br />
VOID A::StartThread()<br />
{<br />
  AfxBeginThread(ThreadProc, this);<br />
}<br />
<br />
LRESULT A::ThreadProc (LPVOID pParam)<br />
{<br />
  A *This = (A*)pParam;<br />
  This->DoThread();<br />
  return 0L;<br />
}<br />
<br />
VOID A::DoThread()<br />
{<br />
  // Do something here...<br />
}

Re: Question about MultiThreading

Cedric Moonen10-Jun-05 2:06

Cedric Moonen

10-Jun-05 2:06

Yes of course...
But the only advantage I see in this method is to avoid having a global function. Is there any other advantage ?

Re: Question about MultiThreading

Stlan10-Jun-05 2:19

Stlan

10-Jun-05 2:19

It's perhaps only a matter of design but I assume that the worker thread is part of the object and is related to its internal working. So for me, it makes sense that the thread procedure be physically a function member of the class so that it can access to other private data (which the global function can't) Anyway I don't like too much global functions in C++.

Re: Question about MultiThreading

David Crow10-Jun-05 6:19

David Crow

10-Jun-05 6:19

See here.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Constructing a parser

dittygrail9-Jun-05 23:33

dittygrail

9-Jun-05 23:33

I need to construct a parser.My application is in MFC.
How to build a parser with simple construction procedure.
It also has to applicable for the project objects.
please avoid the concept of Activex scripting...

Re: Constructing a parser

Stlan10-Jun-05 0:11

Stlan

10-Jun-05 0:11

Not sure to understand what you mean. If you need to parse a string containing items separated by known constant characters, it may be sufficient to use CString::Tokenize; then you need to build a structure representing the logical content of the string, so that it will be easier then to manipulate the data. It's actually a very vast subject.

Re: Constructing a parser

toxcct10-Jun-05 0:24

toxcct

10-Jun-05 0:24

not sure i understand neither, but if you want a not too difficult method to parsing a language, you could read my article VisualCalc...

cheers,

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: Constructing a parser

toxcct10-Jun-05 1:31

toxcct

10-Jun-05 1:31

CodeProject Parsers...[^]

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: Constructing a parser

ThatsAlok10-Jun-05 1:41

ThatsAlok

10-Jun-05 1:41

You getting very fast these days, How dare, you use your HAND for TYPING! Mad | :mad:

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Re: Constructing a parser

ThatsAlok10-Jun-05 1:35

ThatsAlok

10-Jun-05 1:35

dittygrail wrote:
I need to construct a parser.My application is in MFC.

What type of Parser do u want to Create, i.e. XML parser, HTML parser etc.....

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Re: Constructing a parser

toxcct10-Jun-05 1:49

toxcct

10-Jun-05 1:49

ThatsAlok wrote:
What type of Parser do u want to Create, i.e. XML parser, HTML parser etc.....

no, only a parser !!! Laugh | :laugh:

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: Constructing a parser

ThatsAlok10-Jun-05 1:54

ThatsAlok

10-Jun-05 1:54

toxcct wrote:
only a parser

Sigh | :sigh:

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Re: Constructing a parser

Stlan10-Jun-05 1:58

Stlan

10-Jun-05 1:58

With both you discussing here, this is the most colorful message thread I've ever seen on CP Smile | :)

Re: Constructing a parser

ThatsAlok10-Jun-05 2:04

ThatsAlok

10-Jun-05 2:04

Stlan wrote:
With both you discussing here, this is the most colorful message thread I've ever seen on CP

We are Here (Including you) to make life of programmer Colorful Smile | :)

you too can color your USERNAME in Red Smile | :)

, which i believe i have already colored Smile | :)

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Re: Constructing a parser

Stlan10-Jun-05 2:22

Stlan

10-Jun-05 2:22

Oh my! I became a member of the club of the colorful people! So cool! Cool | :cool:

Re: Constructing a parser

ThatsAlok10-Jun-05 2:25

ThatsAlok

10-Jun-05 2:25

Stlan wrote:
Oh my! I became a member of the club of the colorful people! So

But you forget to color your username, Don't worry for this time, I have colored that for you. But this is last time Smile | :)

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Bob Stanneveld10-Jun-05 2:44

Bob Stanneveld

10-Jun-05 2:44

ThatsAlok wrote:
I have colored that for you

How do you color your username?

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

Re: OT

ThatsAlok10-Jun-05 2:52

ThatsAlok

10-Jun-05 2:52

Bob Stanneveld wrote:
How do you color your username?

use HTML tags like this, if you want to color you username RED

<b> <font color=#ff0000>Bob Stanneveld </font></b>

which make your username something like this :-
Bob Stanneveld

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Re: OT

Bob Stanneveld10-Jun-05 2:54

Bob Stanneveld

10-Jun-05 2:54

I thought that the HTML tags didn't work inside your username. Guess it does. Thanks! Big Grin | :-D

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

Re: OT

ThatsAlok10-Jun-05 2:55

ThatsAlok

10-Jun-05 2:55

Bob Stanneveld wrote:
Guess it does.

So whats your new color Smile | :)

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Re: OT

Bob Stanneveld10-Jun-05 2:58

Bob Stanneveld

10-Jun-05 2:58

Nothing special yet. My favorite colours are already taken, blue by you and black by everyone else who doesn't bother to change the colour of their name... Unsure | :~

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

Re: OT

toxcct10-Jun-05 5:18

toxcct

10-Jun-05 5:18

you could glow you name so...

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: Constructing a parser

toxcct10-Jun-05 5:15

toxcct

10-Jun-05 5:15

welcome dear...

Rose | [Rose]

TOXCCT >>> GEII power
[toxcct][VisualCalc]

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