CComObjectRootEx::Lock
If the thread model is multithreaded, this method calls the Win32 API function EnterCriticalSection, which waits until the thread can take ownership of the critical section object obtained through a private data member.
void Lock( );
Remarks
When the protected code finishes executing, the thread must call Unlock to release ownership of the critical section.
If the thread model is single-threaded, this method does nothing.
Requirements
Header: atlcom.h