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| -rw-r--r-- | ace/Singleton.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/ace/Singleton.h b/ace/Singleton.h index 7b40bd353d5..2e108f1ed2d 100644 --- a/ace/Singleton.h +++ b/ace/Singleton.h @@ -39,6 +39,18 @@ class ACE_Singleton : public ACE_Cleanup // scheme to work, a (static) <cleanup> function must be // provided. <ACE_Singleton> provides one so that TYPE doesn't // need to. + // + // NOTE: the best types to use for ACE_LOCK are + // ACE_Recursive_Thread_Mutex and ACE_Null_Mutex. + // ACE_Recursive_Thread_Mutex should be used in multi-threaded + // programs in which it is possible for more than one thread to + // access the <ACE_Singleton<TYPE, ACE_LOCK>> instance. + // ACE_Null_Mutex can be used otherwise. The reason that these + // types of locks are best has to do with their allocation by + // the ACE_Object_Manager. Single ACE_Recursive_Thread_Mutex + // and ACE_Null_Mutex instances are used for all ACE_Singleton + // instantiations. However, other types of locks are allocated + // per ACE_Singleton instantiation. { public: static TYPE *instance (void); |