C / C++ / MFC

mercenary01 wrote:

well its not like I just jumped onto this forum to ask for help, I did spend time on studying he example code and got the drawline working for GDI by modifying the sample codes. I spent more than the better half of 2 days

mercenary01 wrote:

If you don't want to give any positive input why bother giving any input?

//{{AFX_MSG(CYourDialog)
afx_msg void OnPaint();
//}}AFX_MSG
DECLARE_MESSAGE_MAP()

mercenary01 wrote:

Just like to state, that I don't go around telling people how hard I worked or tired my hand on something.

mercenary01 wrote:

What is the simplest method I can use to get lines drawn on dialog boxes?

mercenary01 wrote:

But seriously I don't want anyone to get me wrong

mercenary01 wrote:

ya I got it to work got a piece of code from another forum and modified it to fit the project. Thanks for asking.

Greetings.
--------
M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson

void threadFunction(void *argList)<br />
{<br />
    // Process on varibles.<br />
    _endthread();<br />
}<br />
void className::methodName()<br />
{<br />
    int x = 100;<br />
    _beginthread(&threadFunction, 0, /*what i have to pass over hear*/)<br />
}

void className::methodName()
{
int x = 100;
_beginthread(threadFunction, 0, this)
} 

void threadFunction( void *p )
{
if ( ! p ) return;
className * pClass = (className *) p; // maybe a convenient alias
pClass->m_count++; // where count is class public int data
...
}

BTW In fact there is a direct solution of your problem, and it is so ugly that I cannot resist the temptation to post it :

[modified afterwards Cedric Moonen reply  :-O ].
//-> HERE STARTS BAD CODE
class className;
struct MyUglyThreadArg
{
 className * pClass;
 int * px;
};
class className
{

  ...
  MyUglyThreadArg muta;
  void methodName()
  {
    static int x = 100;
    muta.pClass = this;
    muta.px = &x;
    _beginthread(&threadFunction, 0, &muta);
  }
...
}; 

void threadFunction( void *p )
{
  if ( ! p ) return;
  MyUglyThreadArg *pMuta = (MyUglyThreadArg *) p;
  className * pClass = (className *) p->pClass; 
  pClass->m_count++; // where count is class public int data
  *(pMuta->px) = 200; 
...
}
//<- HERE ENDS BAD CODE

Cedric Moonen wrote:

A better way to deal with it in OOP is to start the thread from within a class and pass the this pointer to the thread function. Then in your function, you can cast it back to a class pointer and call some public method of your class.

CPallini wrote:

is hazardous too: the bug coming out if the class instance goes out-of-scope while thread function is running.

Cedric Moonen wrote:

That's not very usefull: it is kind of a snake that bites its own tail. You pass in a structure which contains a pointer to the class which itself contains the structure. So, what's the point ? So, you still can't pass different 'x' values to different threads (here again, potential race condition). Because I suppose if the OP wanted to do something like that was because he plans to start several threads and pass some specific information to each of them along the this pointer.

Cedric Moonen wrote:

Because I suppose if the OP wanted to do something like that was because he plans to start several threads and pass some specific information to each of them along the this pointer

Cedric Moonen wrote:

There is a workaround that but which is ugly too: create the structure on the heap and delete it inside the thread function.