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lib-of-vs-libs-Poco-include-Poco-ThreadLocal.h / h



  //
  // ThreadLocal.h
  //
  // Id: //poco/1.3/Foundation/include/Poco/ThreadLocal.h#1 
  //
  // Library: Foundation
  // Package: Threading
  // Module:  Thread
  //
  // Definition of the ThreadLocal template and related classes.
  //
  // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
  // and Contributors.
  //
  // Permission is hereby granted, free of charge, to any person or organization
  // obtaining a copy of the software and accompanying documentation covered by
  // this license (the "Software") to use, reproduce, display, distribute,
  // execute, and transmit the Software, and to prepare derivative works of the
  // Software, and to permit third-parties to whom the Software is furnished to
  // do so, all subject to the following:
  // 
  // The copyright notices in the Software and this entire statement, including
  // the above license grant, this restriction and the following disclaimer,
  // must be included in all copies of the Software, in whole or in part, and
  // all derivative works of the Software, unless such copies or derivative
  // works are solely in the form of machine-executable object code generated by
  // a source language processor.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  // DEALINGS IN THE SOFTWARE.
  //
  
  ifndef Foundation_ThreadLocal_INCLUDED
  define Foundation_ThreadLocal_INCLUDED
  
  include "Poco/Foundation.h"
  include <map>
  
  namespace Poco {
  
  class Foundation_API TLSAbstractSlot
This is the base class for all objects that the ThreadLocalStorage class manages. { public: TLSAbstractSlot(); virtual ~TLSAbstractSlot(); }; 

  template <class C>
  class TLSSlot: public TLSAbstractSlot
The Slot template wraps another class so that it can be stored in a ThreadLocalStorage object. This class is used internally, and you must not create instances of it yourself. { public: TLSSlot(): _value() { } ~TLSSlot() { } C& value() { return _value; } private: TLSSlot(const TLSSlot&); TLSSlot& operator = (const TLSSlot&); 

          C _value;
  };
  
  class Foundation_API ThreadLocalStorage
This class manages the local storage for each thread. Never use this class directly, always use the ThreadLocal template for managing thread local storage. { public: ThreadLocalStorage(); Creates the TLS. ~ThreadLocalStorage(); Deletes the TLS. 

          TLSAbstractSlot*& get(const void* key);
Returns the slot for the given key. static ThreadLocalStorage& current(); Returns the TLS object for the current thread (which may also be the main thread). static void clear(); Clears the current thread's TLS object. Does nothing in the main thread. private: typedef std::map<const void*, TLSAbstractSlot*> TLSMap; TLSMap _map; 

          friend class Thread;
  };
  
  template <class C>
  class ThreadLocal
This template is used to declare type safe thread local variables. It can basically be used like a smart pointer class with the special feature that it references a different object in every thread. The underlying object will be created when it is referenced for the first time. See the NestedDiagnosticContext class for an example how to use this template. Every thread only has access to its own thread local data. There is no way for a thread to access another thread's local data. { typedef TLSSlot<C> Slot; 

  public:
          ThreadLocal()
          {
          }
          
          ~ThreadLocal()
          {
          }
          
          C* operator -> ()
          {
                  return &get();
          }
          
          C& operator * ()
"Dereferences" the smart pointer and returns a reference to the underlying data object. The reference can be used to modify the object. { return get(); } 

          C& get()
Returns a reference to the underlying data object. The reference can be used to modify the object. { TLSAbstractSlot*& p = ThreadLocalStorage::current().get(this); if (!p) p = new Slot; return static_cast<Slot*>(p)->value(); } private: ThreadLocal(const ThreadLocal&); ThreadLocal& operator = (const ThreadLocal&); }; 

  } // namespace Poco
  
  endif // Foundation_ThreadLocal_INCLUDED
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

(C) Æliens 04/09/2009

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