CSemaphore with Lock() and Unlock()

// YourDlg.h
...
class CYourDlg : public CDialog
{
...
  // gate control:
  static CSemaphore sm_cSemaphore;
  // worker threads proc:
  static DWORD WINAPI EntertainmentProc(CYourDlg* pcDlg);
...
  // some function to be limited by threads access:
  void ProcessPyrotechnics(); 
...
public:
...
};
...
  

// YourDlg.cpp
...
// gate for two threads only:
/*static*/ CSemaphore CYourDlg::sm_cSemaphore(0, 2);
 

// loop for possible threads:
/*static*/ DWORD WINAPI CYourDlg::EntertainmentProc(CYourDlg* pcDlg)
{
  if (pcDlg) {
    while (pcDlg->m_bWorkerRunning) {
      // An exception secure object:
      CSingleLock cLock(&sm_cSemaphore);
      // entry or wait:
      cLock.Lock();
      // entered, we are one of two allowed threads now:
      if (pcDlg->m_bWorkerRunning) {
        pcDlg->ProcessPyrotechnics();
      }
      // done, release the locking:
      cLock.Unlock();
      ...
    }
  }
  return 0;
}
...

HANDLE g_Semaphore;
// Create a semaphore with initial and max.
g_Semaphore = CreateSemaphore(  NULL,   4, 4,  NULL);  
DWORD dwWaitResult; 
//take ownership
dwWaitResult = WaitForSingleObject(   g_Semaphore, 0L);
// Check the ownership

// Release Semaphore
ReleaseSemaphore(  g_Semaphore,  1,  NULL) ;