C / C++ / MFC

//in header file:
...
//}}AFX_MSG
afx_msg LRESULT OnWorkerMessage(WPARAM wParam, LPARAM lParam);

//in cpp. ON_MESSAGE should go after MFC messages:

//}}AFX_MSG_MAP
ON_MESSAGE(WM_USER+1, OnWorkerMessage)
....

LRESULT CMyDlg::OnWorkerMessage(WPARAM /* wParam */, LPARAM /* lParam */)
{
...
}

#include <iostreamᡊe9ac73-238b-46be-991d-0f050c37248d
using namespace std;

class Base
{
protected:
	static int _iIndex;
	static Base* _pAddress;

	int _iId;
	Base* _pPrev;

public:
	Base() {
		_iId = ++_iIndex;
		_pPrev = _pAddress;
		_pAddress = this;
	}

	Base& operator==(Base& ref) {
		ref._pPrev = this;
		return *this;
	}

	int Bomb() {
		cout << _iId << " -> ";
		_sleep(500);
		if(!_pPrev) {
			cout << "\nChain broken!\n";
			return 1;
		}
		return _pPrev->Bomb();
	}
};

int Base::_iIndex = 0;
Base* Base::_pAddress = 0;

int main()
{
	Base a[20];

	a[19] == a[0];
	return a[19].Bomb();
}

CMyclass & CMyclass::operator=(const CMyclass & toCopy)
{
  if (this != &toCopy)
  {
    m_iCount = toCopy.m_iCount;
    m_iIndex = toCopy.m_iIndex;
  }
  return *this;
}

#include <iostreamᡊe9ac73-238b-46be-991d-0f050c37248d
using namespace std;

class Base
{
public:
	Base() { }
	int a;
	Base(const Base& ref)
	{
		this->a = ref.a;
	}
};

void main()
{
	Base a;
	Base b;

	a.a = 3;
	b = a;

	cout << b.a << endl;
}

1. Create a member variable to store the current tab index.
   
2. Create an array member variable to hold all of the index values for the currently disabled tabs.
   
3. Handle the TCN_SELCHANGING notification message to set the current tab index.
   
4. Handle the TCN_SELCHANGED notification message to decide if you want to enable the tab to be activated. If you don’t, you must post a PSM_SETCURSEL message. In this message, the last active tab index is specified.