INFO: Critical Sections Versus Mutexes

• Microsoft Win32 Application Programming Interface (API), included with:
  • Microsoft Windows NT versions 3.5, 3.51, 4.0
  • Microsoft Windows 95
  • Microsoft Windows 2000

SUMMARY

Critical sections and mutexes provide synchronization that is very similar, except that critical sections can be used only by the threads of a single process. There are two areas to consider when choosing which method to use within a single process:

1. Speed. The Synchronization overview says the following about critical sections:

   ... critical section objects provide a slightly faster, more efficient mechanism for mutual-exclusion synchronization.

   Critical sections use a processor-specific test and set instruction to determine mutual exclusion.



2. Deadlock. The Synchronization overview says the following about mutexes:

   If a thread terminates without releasing its ownership of a mutex object, the mutex is considered to be abandoned. A waiting thread can acquire ownership of an abandoned mutex, but the wait function's return value indicates that the mutex is abandoned.

   WaitForSingleObject() will return WAIT_ABANDONED for a mutex that has been abandoned. However, the resource that the mutex is protecting is left in an unknown state.
   
   There is no way to tell whether a critical section has been abandoned.

Additional query words: 3.50

Keywords : kbKernBase kbWinOS2000 kbThread kbThreadSync kbDSupport kbGrpKernBase
Version : winnt:3.5,3.51,4.0
Platform : winnt
Issue type : kbinfo