/usr/include/ucommon/atomic.h is in libucommon-dev 6.0.7-1.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 | // Copyright (C) 2006-2010 David Sugar, Tycho Softworks.
//
// This file is part of GNU uCommon C++.
//
// GNU uCommon C++ is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU uCommon C++ is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with GNU uCommon C++. If not, see <http://www.gnu.org/licenses/>.
/**
* Atomic pointers and locks. These are meant to use atomic CPU operations
* and hence offer maximum performance.
* @file ucommon/atomic.h
* @author David Sugar <dyfet@gnutelephony.org>
*/
#ifndef _UCOMMON_ATOMIC_H_
#define _UCOMMON_ATOMIC_H_
#ifndef _UCOMMON_CONFIG_H_
#include <ucommon/platform.h>
#endif
NAMESPACE_UCOMMON
/**
* Generic atomic class for referencing atomic objects and static functions.
* We have an atomic counter and spinlock, and in the future we may add
* other atomic classes and atomic manipulations needed to create lockfree
* data structures. The atomic classes use mutexes if no suitable atomic
* code is available.
* @author David Sugar <dyfet@gnutelephony.org>
*/
class __EXPORT atomic
{
public:
/**
* Set to true if atomics have to be simulated with mutexes.
*/
static const bool simulated;
/**
* Atomic counter class. Can be used to manipulate value of an
* atomic counter without requiring explicit thread locking.
* @author David Sugar <dyfet@gnutelephony.org>
*/
class __EXPORT counter
{
private:
volatile long value;
public:
counter(long initial = 0);
long operator++();
long operator--();
long operator+=(long offset);
long operator-=(long offset);
inline operator long()
{return (long)(value);};
inline long operator*()
{return value;};
};
/**
* Atomic spinlock class. Used as high-performance sync lock between
* threads.
* @author David Sugar <dyfet@gnutelephony.org>
*/
class __EXPORT spinlock
{
private:
volatile long value;
public:
/**
* Construct and initialize spinlock.
*/
spinlock();
/**
* Acquire the lock. If the lock is not acquired, one "spins"
* by doing something else. One suggestion is using thread::yield.
* @return true if acquired.
*/
bool acquire(void);
/**
* Release an acquired spinlock.
*/
void release(void);
};
};
END_NAMESPACE
#endif
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