Start the same thread more than once with different param! <URGENT>

[balzarini]

Hi Everybody!

I'm making an MFC application that simulate a routing algorithm.

I have some nodes that are called clusterheads that have the control all the nodes in the cluster (members).

Struct:

p->ch bool: is or not a CH?
p->nCH int: number of the members of this CH
p->CM[] int[]: array with all the ID the members of the cluster.


my code is:

void CSimDlg::StartSS(void)
{
	CString msg;
	
	//scan all nodes untill you find a ClusterHead


	for (int i=0; i<m_vecNodes.size(); i++)
	{
		NODE* p = m_vecNodes[i];
		
		if(p->ch){
			
			//Cluster Head found

			inttopass=i;

			_beginthread(StaticClusterStart, 0, this);

			break;
		}
	}


}

void CSimDlg::StaticClusterStart(void * param)
{
	CSimDlg * pThis = (CSimDlg *)param;
	ASSERT(pThis != NULL);
	pThis->ClusterStart();
}

void CSimDlg::ClusterStart(void)
{
	NODE* p = m_vecNodes[inttopass];

	// for the ClusterHead "inttopass" activate one node each SST/p->nCM seconds

	if(p->ch){

		for(int j=0; j<p->nCM; j++){
		ActivateNode(p->CM[j]);
		Sleep(SST/p->nCM);
	}
	
	_endthread();
}

Now:
If I run this code everything is fine, and thanks to the "break" after "_beginthread(StaticClusterStart, 0, this);" I take the first Cluster head in the list and I start a thread that activate each node of it.

The problem is that I need to start the same funcion ClusterStart(void) for each Cluster head, at the same time.
so the best thing witll be to do something like this:

for (int i=0; i<m_vecNodes.size(); i++)
	{
		NODE* p = m_vecNodes[i];
		
		if(p->ch){
			
			//Cluster Head found

			inttopass=i;

			BEGIN a thread for CH i; 
		}
	}

Plus the number of CH is variable each time i run the program so I cannot make different function like:
_beginthread(StaticClusterStart1, 0, this);
_beginthread(StaticClusterStart2, 0, this);
...
_beginthread(StaticClusterStartN, 0, this);


Do you have any ideas how can I solve this problem??? Any suggestion or any comment to the code?

One more thing: how can I pass the int "intopass" from void CSimDlg::StartSS(void) to void CSimDlg::ClusterStart(void) ???

[kuphryn]

What's the question?

Kuphryn

[kirants]

Add a struct

struct ThreadParam
{
   CSimDlg* m_pDialog;
    int   m_nNodeIndex;
};

Where you beginthread, do this:

if(p->ch)
{
   //Cluster Head found
   ThreadParam* pParam = new ThreadParam;
   pParam->m_pDialog = this;
   pParam->m_nNodeInxex = i;
   _beginthread(StaticClusterStart, 0, (void*)pParam);
   break;
}

In your thread proc:

void CSimDlg::StaticClusterStart(void * param)
{
	ThreadParam* pParam = (ThreadParam* pParam)param;
	pParam->m_pDialog->ClusterStart(pParam->m_nNodeIndex);
        delete pParam;
}

Modify ClusterStart as:

void CSimDlg::ClusterStart(int nNodeIndex)
{
	NODE* p = m_vecNodes[nNodeIndex];
	if(p->ch)
       {
         for(int j=0; j<p->nCM; j++){
	 ActivateNode(p->CM[j]);
	 Sleep(SST/p->nCM);
       }
}

[Arjay]

Where you beginthread, do this:

if(p->ch)
{
  //Cluster Head found
  ThreadParam* pParam = new ThreadParam;
  pParam->m_pDialog = this;
  pParam->m_nNodeInxex = i;
  _beginthread(StaticClusterStart, 0, (void*)pParam);
  break;
}

Shouldn't the ThreadParam* pParam be move into class scope to avoid the memory leak?

Arjay

[kirants]

Not sure. The OP is spawning threads from the class. So, if it were to be moved to class scope, he'd have to have an array of ThreadParam structures, right ?

[Arjay]

Kirant, I missed where you delete the pParam in the thread function - my bad.

[kirants]

You will need to store the return value of _beginthread which is a thread handle.

So,
HANDLE hThread = (HANDLE)_beginthread(....);

And then, when you want to wait for it to end..

WaitForSingleObject(hThread,INFINITE);

This function will wait till the handle is signalled and in case of thread handles, they are signalled when the thread terminates.

Please search on these APIs and you will find enough info. Just providing you the starting point as to where to look.

Also, you may want to look at _beginthreadex function.

There are times when you want to use this instead of _beginthread when you are using crt calls. Please read thru this also on MSDN.