Insane_DNS/libraries/asio-1.28.1/include/asio/detail/posix_global.hpp

81 lines
1.7 KiB
C++

//
// detail/posix_global.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2023 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// 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)
//
#ifndef ASIO_DETAIL_POSIX_GLOBAL_HPP
#define ASIO_DETAIL_POSIX_GLOBAL_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/config.hpp"
#if defined(ASIO_HAS_PTHREADS)
#include <exception>
#include <pthread.h>
#include "asio/detail/push_options.hpp"
namespace asio {
namespace detail {
template <typename T>
struct posix_global_impl
{
// Helper function to perform initialisation.
static void do_init()
{
instance_.static_ptr_ = instance_.ptr_ = new T;
}
// Destructor automatically cleans up the global.
~posix_global_impl()
{
delete static_ptr_;
}
static ::pthread_once_t init_once_;
static T* static_ptr_;
static posix_global_impl instance_;
T* ptr_;
};
template <typename T>
::pthread_once_t posix_global_impl<T>::init_once_ = PTHREAD_ONCE_INIT;
template <typename T>
T* posix_global_impl<T>::static_ptr_ = 0;
template <typename T>
posix_global_impl<T> posix_global_impl<T>::instance_;
template <typename T>
T& posix_global()
{
int result = ::pthread_once(
&posix_global_impl<T>::init_once_,
&posix_global_impl<T>::do_init);
if (result != 0)
std::terminate();
return *posix_global_impl<T>::instance_.ptr_;
}
} // namespace detail
} // namespace asio
#include "asio/detail/pop_options.hpp"
#endif // defined(ASIO_HAS_PTHREADS)
#endif // ASIO_DETAIL_POSIX_GLOBAL_HPP