/usr/include/boost/thread/win32/once.hpp is in libboost1.46-dev 1.46.1-7ubuntu3.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 | #ifndef BOOST_THREAD_WIN32_ONCE_HPP
#define BOOST_THREAD_WIN32_ONCE_HPP
// once.hpp
//
// (C) Copyright 2005-7 Anthony Williams
// (C) Copyright 2005 John Maddock
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#include <cstring>
#include <cstddef>
#include <boost/assert.hpp>
#include <boost/static_assert.hpp>
#include <boost/detail/interlocked.hpp>
#include <boost/thread/win32/thread_primitives.hpp>
#include <boost/thread/win32/interlocked_read.hpp>
#include <boost/config/abi_prefix.hpp>
#ifdef BOOST_NO_STDC_NAMESPACE
namespace std
{
using ::memcpy;
using ::ptrdiff_t;
}
#endif
namespace boost
{
struct once_flag
{
long status;
long count;
};
#define BOOST_ONCE_INIT {0,0}
namespace detail
{
#ifdef BOOST_NO_ANSI_APIS
typedef wchar_t once_char_type;
#else
typedef char once_char_type;
#endif
unsigned const once_mutex_name_fixed_length=54;
unsigned const once_mutex_name_length=once_mutex_name_fixed_length+
sizeof(void*)*2+sizeof(unsigned long)*2+1;
template <class I>
void int_to_string(I p, once_char_type* buf)
{
for(unsigned i=0; i < sizeof(I)*2; ++i,++buf)
{
#ifdef BOOST_NO_ANSI_APIS
once_char_type const a=L'A';
#else
once_char_type const a='A';
#endif
*buf = a + static_cast<once_char_type>((p >> (i*4)) & 0x0f);
}
*buf = 0;
}
inline void name_once_mutex(once_char_type* mutex_name,void* flag_address)
{
#ifdef BOOST_NO_ANSI_APIS
static const once_char_type fixed_mutex_name[]=L"Local\\{C15730E2-145C-4c5e-B005-3BC753F42475}-once-flag";
#else
static const once_char_type fixed_mutex_name[]="Local\\{C15730E2-145C-4c5e-B005-3BC753F42475}-once-flag";
#endif
BOOST_STATIC_ASSERT(sizeof(fixed_mutex_name) ==
(sizeof(once_char_type)*(once_mutex_name_fixed_length+1)));
std::memcpy(mutex_name,fixed_mutex_name,sizeof(fixed_mutex_name));
detail::int_to_string(reinterpret_cast<std::ptrdiff_t>(flag_address),
mutex_name + once_mutex_name_fixed_length);
detail::int_to_string(win32::GetCurrentProcessId(),
mutex_name + once_mutex_name_fixed_length + sizeof(void*)*2);
}
inline void* open_once_event(once_char_type* mutex_name,void* flag_address)
{
if(!*mutex_name)
{
name_once_mutex(mutex_name,flag_address);
}
#ifdef BOOST_NO_ANSI_APIS
return ::boost::detail::win32::OpenEventW(
#else
return ::boost::detail::win32::OpenEventA(
#endif
::boost::detail::win32::synchronize |
::boost::detail::win32::event_modify_state,
false,
mutex_name);
}
inline void* create_once_event(once_char_type* mutex_name,void* flag_address)
{
if(!*mutex_name)
{
name_once_mutex(mutex_name,flag_address);
}
#ifdef BOOST_NO_ANSI_APIS
return ::boost::detail::win32::CreateEventW(
#else
return ::boost::detail::win32::CreateEventA(
#endif
0,::boost::detail::win32::manual_reset_event,
::boost::detail::win32::event_initially_reset,
mutex_name);
}
}
template<typename Function>
void call_once(once_flag& flag,Function f)
{
// Try for a quick win: if the procedure has already been called
// just skip through:
long const function_complete_flag_value=0xc15730e2;
long const running_value=0x7f0725e3;
long status;
bool counted=false;
detail::win32::handle_manager event_handle;
detail::once_char_type mutex_name[detail::once_mutex_name_length];
mutex_name[0]=0;
while((status=::boost::detail::interlocked_read_acquire(&flag.status))
!=function_complete_flag_value)
{
status=BOOST_INTERLOCKED_COMPARE_EXCHANGE(&flag.status,running_value,0);
if(!status)
{
try
{
if(!event_handle)
{
event_handle=detail::open_once_event(mutex_name,&flag);
}
if(event_handle)
{
::boost::detail::win32::ResetEvent(event_handle);
}
f();
if(!counted)
{
BOOST_INTERLOCKED_INCREMENT(&flag.count);
counted=true;
}
BOOST_INTERLOCKED_EXCHANGE(&flag.status,function_complete_flag_value);
if(!event_handle &&
(::boost::detail::interlocked_read_acquire(&flag.count)>1))
{
event_handle=detail::create_once_event(mutex_name,&flag);
}
if(event_handle)
{
::boost::detail::win32::SetEvent(event_handle);
}
break;
}
catch(...)
{
BOOST_INTERLOCKED_EXCHANGE(&flag.status,0);
if(!event_handle)
{
event_handle=detail::open_once_event(mutex_name,&flag);
}
if(event_handle)
{
::boost::detail::win32::SetEvent(event_handle);
}
throw;
}
}
if(!counted)
{
BOOST_INTERLOCKED_INCREMENT(&flag.count);
counted=true;
status=::boost::detail::interlocked_read_acquire(&flag.status);
if(status==function_complete_flag_value)
{
break;
}
if(!event_handle)
{
event_handle=detail::create_once_event(mutex_name,&flag);
continue;
}
}
BOOST_VERIFY(!::boost::detail::win32::WaitForSingleObject(
event_handle,::boost::detail::win32::infinite));
}
}
}
#include <boost/config/abi_suffix.hpp>
#endif
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