/usr/include/dlib/threads/rmutex_extension.h is in libdlib-dev 18.18-1.
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 99 100 101 102 103 104 105 106 107 108 | // Copyright (C) 2005 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_RMUTEX_EXTENSIOn_
#define DLIB_RMUTEX_EXTENSIOn_
#include "threads_kernel.h"
#include "rmutex_extension_abstract.h"
namespace dlib
{
// ----------------------------------------------------------------------------------------
class rmutex
{
/*!
INITIAL VALUE
count == 0
thread_id == 0
CONVENTION
- count == lock_count()
- if (no thread currently has a lock on this mutex) then
- count == 0
- else
- count == the number of times the thread that owns this mutex has
called lock()
- thread_id == the id of this thread.
!*/
public:
rmutex (
) : s(m),
thread_id(0),
count(0)
{}
~rmutex (
)
{}
unsigned long lock_count (
) const
{
return count;
}
void lock (
unsigned long times = 1
) const
{
const thread_id_type current_thread_id = get_thread_id();
m.lock();
if (thread_id == current_thread_id)
{
// we already own this mutex in this case
count += times;
}
else
{
// wait for our turn to claim this rmutex
while (count != 0)
s.wait();
count = times;
thread_id = current_thread_id;
}
m.unlock();
}
void unlock (
unsigned long times = 1
) const
{
const thread_id_type current_thread_id = get_thread_id();
m.lock();
if (thread_id == current_thread_id)
{
if (count <= times)
{
count = 0;
s.signal();
}
else
{
count -= times;
}
}
m.unlock();
}
private:
mutex m;
signaler s;
mutable thread_id_type thread_id;
mutable unsigned long count;
// restricted functions
rmutex(rmutex&); // copy constructor
rmutex& operator=(rmutex&); // assignment operator
};
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_RMUTEX_EXTENSIOn_
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