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TSpinMutex.hxx
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1 // @(#)root/thread
2 // Author: Danilo Piparo, 2016
3 
4 /*************************************************************************
5  * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *
6  * All rights reserved. *
7  * *
8  * For the licensing terms see $ROOTSYS/LICENSE. *
9  * For the list of contributors see $ROOTSYS/README/CREDITS. *
10  *************************************************************************/
11 
12 #ifndef ROOT_TSpinMutex
13 #define ROOT_TSpinMutex
14 
15 #include <atomic>
16 
17 namespace ROOT {
18 
19  /**
20  * \class ROOT::TSpinMutex
21  * \brief A spin mutex class which respects the STL interface for mutexes.
22  * \ingroup Multicore
23  * This class allows to acquire spin locks also in combination with templates in the STL such as
24  * <a href="http://en.cppreference.com/w/cpp/thread/unique_lock">std::unique_lock</a> or
25  * <a href="http://en.cppreference.com/w/cpp/thread/condition_variable_any">std::condition_variable_any</a>.
26  * For example:
27  *
28  * ~~~ {.cpp}
29  * ROOT::TSpinMutex m;
30  * std::condition_variable cv;
31  * bool ready = false;
32  *
33  * void worker_thread()
34  * {
35  * // Wait until main() sends data
36  * std::unique_lock<ROOT::TSpinMutex> lk(m);
37  * cv.wait(lk, []{return ready;});
38  * [...]
39  * }
40  * ~~~ {.cpp}
41  */
42  class TSpinMutex {
43 
44  private:
45  std::atomic_flag fAFlag = ATOMIC_FLAG_INIT;
46 
47  public:
48  TSpinMutex() = default;
49  TSpinMutex(const TSpinMutex&) = delete;
50  ~TSpinMutex() = default;
51  TSpinMutex& operator=(const TSpinMutex&) = delete;
52 
53  void lock() { while (fAFlag.test_and_set(std::memory_order_acquire)); }
54  void unlock() { fAFlag.clear(std::memory_order_release); }
55  bool try_lock() { return !fAFlag.test_and_set(std::memory_order_acquire); }
56 
57  };
58 }
59 
60 #endif
ROOT::TSpinMutex
A spin mutex class which respects the STL interface for mutexes.
Definition: TSpinMutex.hxx:48
ROOT::TSpinMutex::lock
void lock()
Definition: TSpinMutex.hxx:59
ROOT::TSpinMutex::operator=
TSpinMutex & operator=(const TSpinMutex &)=delete
ROOT::TSpinMutex::fAFlag
std::atomic_flag fAFlag
Definition: TSpinMutex.hxx:51
ROOT::TSpinMutex::try_lock
bool try_lock()
Definition: TSpinMutex.hxx:61
ROOT::TSpinMutex::~TSpinMutex
~TSpinMutex()=default
ROOT::TSpinMutex::unlock
void unlock()
Definition: TSpinMutex.hxx:60
ROOT::TSpinMutex::TSpinMutex
TSpinMutex()=default
ROOT
VSD Structures.
Definition: StringConv.hxx:21