CComMultiThreadModelNoCS is similar to CComMultiThreadModel in that it provides thread-safe methods for incrementing and decrementing a variable. However, when you reference a critical section class through CComMultiThreadModelNoCS, methods such as Lock and Unlock will do nothing.
Typically, you use CComMultiThreadModelNoCS through the ThreadModelNoCS typedef name. This typedef is defined in CComMultiThreadModelNoCS, CComMultiThreadModel, and CComSingleThreadModel.
In addition to ThreadModelNoCS, CComMultiThreadModelNoCS defines AutoCriticalSection and CriticalSection. These latter two typedef names reference CComFakeCriticalSection, which provides empty methods associated with obtaining and releasing a critical section.