TRWLock

    public:

                      TRWLock()
                      TRWLock(const TRWLock& l)
              virtual ~TRWLock()
       static TClass* Class()
      virtual TClass* IsA() const
             TRWLock& operator=(const TRWLock&)
                Int_t ReadLock()
                Int_t ReadUnLock()
         virtual void ShowMembers(TMemberInspector& insp, char* parent)
         virtual void Streamer(TBuffer& b)
                 void StreamerNVirtual(TBuffer& b)
                Int_t WriteLock()
                Int_t WriteUnLock()

    private:

           Int_t fReaders   number of readers
           Int_t fWriters   number of writers
          TMutex fMutex     rwlock mutex
      TCondition fLockFree  rwlock condition variable

Class Description

                                                                      
 TRWLock                                                              
                                                                      
 This class implements a reader/writer lock. A rwlock allows          
 a resource to be accessed by multiple reader threads but only        
 one writer thread.                                                   
                                                                      

 Create reader/write lock.

 Obtain a reader lock. Returns always 0.

 Unlock reader lock. Returns -1 if thread was not locked,
 0 if everything ok.

 Obtain a writer lock. Returns always 0.

 Unlock writer lock. Returns -1 if thread was not locked,
 0 if everything ok.