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TAtomicCountGcc.h
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1// @(#)root/thread:$Id$
2// Author: Fons Rademakers 14/11/06
3
4/*************************************************************************
5 * Copyright (C) 1995-2006, 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_TAtomicCountGcc
13#define ROOT_TAtomicCountGcc
14
15
16//////////////////////////////////////////////////////////////////////////
17// //
18// TAtomicCountGcc //
19// //
20// Class providing atomic operations on a long. Setting, getting, //
21// incrementing and decrementing are atomic, thread safe, operations. //
22// //
23// This implementation uses GNU libstdc++ v3 atomic primitives, see //
24// http://gcc.gnu.org/onlinedocs/porting/Thread-safety.html. //
25// //
26// ATTENTION: Don't use this file directly, it is included by //
27// TAtomicCount.h. //
28// //
29//////////////////////////////////////////////////////////////////////////
30
31#ifndef ROOT_TAtomicCount
32# error This should be #included only by TAtomicCount.h. Please #include TAtomicCount.h.
33#endif //ROOT_TAtomicCount
34
35#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 2) || \
36 (defined(__APPLE_CC__) && __APPLE_CC__ > 5000 && !defined(MAC_OS_X_VERSION_10_6))
37#include <bits/atomicity.h>
38#else
39#include <ext/atomicity.h>
40#endif
41
42#if defined(__GLIBCXX__) // g++ 3.4+
43
44using __gnu_cxx::__atomic_add;
45using __gnu_cxx::__exchange_and_add;
46
47#endif
48
49class TAtomicCount {
50private:
51 mutable _Atomic_word fCnt; // counter
52
53 TAtomicCount(const TAtomicCount &) = delete;
55
56public:
57 explicit TAtomicCount(Long_t v) : fCnt(v) { }
58 void operator++() { __atomic_add(&fCnt, 1); }
59 Long_t operator--() { return __exchange_and_add(&fCnt, -1) - 1; }
60 operator long() const { return __exchange_and_add(&fCnt, 0); }
61 void Set(Long_t v) {
62 fCnt = v;
63#ifdef _GLIBCXX_WRITE_MEM_BARRIER
64#if !(defined(__INTEL_COMPILER) && defined(__ia64__)) //ICC doesn't support inline asm on IA-64
65 _GLIBCXX_WRITE_MEM_BARRIER;
66#endif
67#endif
68 }
69 Long_t Get() const { return __exchange_and_add(&fCnt, 0); }
70};
71
72#endif
long Long_t
Definition: RtypesCore.h:54
Long_t Get() const
TAtomicCount(const TAtomicCount &)=delete
_Atomic_word fCnt
TAtomicCount(Long_t v)
Long_t operator--()
TAtomicCount & operator=(const TAtomicCount &)=delete
void Set(Long_t v)