CComMultiThreadModel

CComMultiThreadModel is a C++ template class provided by the Active Template Library (ATL) for managing COM object multithreading. It defines how a COM object handles incoming requests from multiple threads concurrently. The core idea is to provide a thread-safe way to manage reference counting and object lifetime.

This model offers a default implementation that is suitable for many COM server scenarios. It typically uses atomic operations or critical sections to protect shared data, such as the object's reference count. When an object is created using CComMultiThreadModel, its internal mechanisms ensure that operations like AddRef and Release are executed atomically, preventing race conditions where multiple threads might try to modify the reference count simultaneously. This is crucial for maintaining the integrity of the COM object and preventing premature deallocation or memory corruption.

The CComMultiThreadModel is often used in conjunction with other ATL classes, such as CComObjectRootEx. The CComObjectRootEx class acts as the base class for COM objects and utilizes the threading model specified by CComMultiThreadModel to manage the object's lifetime and internal state. Developers can choose different threading models provided by ATL, such as CComSingleThreadModel or CComSTAThreadModel, depending on their specific application requirements and the COM apartment model they intend to use. CComMultiThreadModel represents a general-purpose, thread-safe approach for COM object management in multithreaded environments.