boost/asio/detail/impl/win_iocp_socket_service_base.ipp
// // detail/impl/win_iocp_socket_service_base.ipp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2024 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 BOOST_ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP #define BOOST_ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/config.hpp> #if defined(BOOST_ASIO_HAS_IOCP) #include <boost/asio/detail/win_iocp_socket_service_base.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { namespace detail { win_iocp_socket_service_base::win_iocp_socket_service_base( execution_context& context) : context_(context), iocp_service_(use_service<win_iocp_io_context>(context)), reactor_(0), connect_ex_(0), nt_set_info_(0), mutex_(), impl_list_(0) { } void win_iocp_socket_service_base::base_shutdown() { // Close all implementations, causing all operations to complete. boost::asio::detail::mutex::scoped_lock lock(mutex_); base_implementation_type* impl = impl_list_; while (impl) { close_for_destruction(*impl); impl = impl->next_; } } void win_iocp_socket_service_base::construct( win_iocp_socket_service_base::base_implementation_type& impl) { impl.socket_ = invalid_socket; impl.state_ = 0; impl.cancel_token_.reset(); #if defined(BOOST_ASIO_ENABLE_CANCELIO) impl.safe_cancellation_thread_id_ = 0; #endif // defined(BOOST_ASIO_ENABLE_CANCELIO) // Insert implementation into linked list of all implementations. boost::asio::detail::mutex::scoped_lock lock(mutex_); impl.next_ = impl_list_; impl.prev_ = 0; if (impl_list_) impl_list_->prev_ = &impl; impl_list_ = &impl; } void win_iocp_socket_service_base::base_move_construct( win_iocp_socket_service_base::base_implementation_type& impl, win_iocp_socket_service_base::base_implementation_type& other_impl) noexcept { impl.socket_ = other_impl.socket_; other_impl.socket_ = invalid_socket; impl.state_ = other_impl.state_; other_impl.state_ = 0; impl.cancel_token_ = other_impl.cancel_token_; other_impl.cancel_token_.reset(); #if defined(BOOST_ASIO_ENABLE_CANCELIO) impl.safe_cancellation_thread_id_ = other_impl.safe_cancellation_thread_id_; other_impl.safe_cancellation_thread_id_ = 0; #endif // defined(BOOST_ASIO_ENABLE_CANCELIO) // Insert implementation into linked list of all implementations. boost::asio::detail::mutex::scoped_lock lock(mutex_); impl.next_ = impl_list_; impl.prev_ = 0; if (impl_list_) impl_list_->prev_ = &impl; impl_list_ = &impl; } void win_iocp_socket_service_base::base_move_assign( win_iocp_socket_service_base::base_implementation_type& impl, win_iocp_socket_service_base& other_service, win_iocp_socket_service_base::base_implementation_type& other_impl) { close_for_destruction(impl); if (this != &other_service) { // Remove implementation from linked list of all implementations. boost::asio::detail::mutex::scoped_lock lock(mutex_); if (impl_list_ == &impl) impl_list_ = impl.next_; if (impl.prev_) impl.prev_->next_ = impl.next_; if (impl.next_) impl.next_->prev_= impl.prev_; impl.next_ = 0; impl.prev_ = 0; } impl.socket_ = other_impl.socket_; other_impl.socket_ = invalid_socket; impl.state_ = other_impl.state_; other_impl.state_ = 0; impl.cancel_token_ = other_impl.cancel_token_; other_impl.cancel_token_.reset(); #if defined(BOOST_ASIO_ENABLE_CANCELIO) impl.safe_cancellation_thread_id_ = other_impl.safe_cancellation_thread_id_; other_impl.safe_cancellation_thread_id_ = 0; #endif // defined(BOOST_ASIO_ENABLE_CANCELIO) if (this != &other_service) { // Insert implementation into linked list of all implementations. boost::asio::detail::mutex::scoped_lock lock(other_service.mutex_); impl.next_ = other_service.impl_list_; impl.prev_ = 0; if (other_service.impl_list_) other_service.impl_list_->prev_ = &impl; other_service.impl_list_ = &impl; } } void win_iocp_socket_service_base::destroy( win_iocp_socket_service_base::base_implementation_type& impl) { close_for_destruction(impl); // Remove implementation from linked list of all implementations. boost::asio::detail::mutex::scoped_lock lock(mutex_); if (impl_list_ == &impl) impl_list_ = impl.next_; if (impl.prev_) impl.prev_->next_ = impl.next_; if (impl.next_) impl.next_->prev_= impl.prev_; impl.next_ = 0; impl.prev_ = 0; } boost::system::error_code win_iocp_socket_service_base::close( win_iocp_socket_service_base::base_implementation_type& impl, boost::system::error_code& ec) { if (is_open(impl)) { BOOST_ASIO_HANDLER_OPERATION((iocp_service_.context(), "socket", &impl, impl.socket_, "close")); // Check if the reactor was created, in which case we need to close the // socket on the reactor as well to cancel any operations that might be // running there. select_reactor* r = static_cast<select_reactor*>( interlocked_compare_exchange_pointer( reinterpret_cast<void**>(&reactor_), 0, 0)); if (r) r->deregister_descriptor(impl.socket_, impl.reactor_data_, true); socket_ops::close(impl.socket_, impl.state_, false, ec); if (r) r->cleanup_descriptor_data(impl.reactor_data_); } else { ec = boost::system::error_code(); } impl.socket_ = invalid_socket; impl.state_ = 0; impl.cancel_token_.reset(); #if defined(BOOST_ASIO_ENABLE_CANCELIO) impl.safe_cancellation_thread_id_ = 0; #endif // defined(BOOST_ASIO_ENABLE_CANCELIO) return ec; } socket_type win_iocp_socket_service_base::release( win_iocp_socket_service_base::base_implementation_type& impl, boost::system::error_code& ec) { if (!is_open(impl)) return invalid_socket; cancel(impl, ec); if (ec) return invalid_socket; nt_set_info_fn fn = get_nt_set_info(); if (fn == 0) { ec = boost::asio::error::operation_not_supported; return invalid_socket; } HANDLE sock_as_handle = reinterpret_cast<HANDLE>(impl.socket_); ULONG_PTR iosb[2] = { 0, 0 }; void* info[2] = { 0, 0 }; if (fn(sock_as_handle, iosb, &info, sizeof(info), 61 /* FileReplaceCompletionInformation */)) { ec = boost::asio::error::operation_not_supported; return invalid_socket; } socket_type tmp = impl.socket_; impl.socket_ = invalid_socket; return tmp; } boost::system::error_code win_iocp_socket_service_base::cancel( win_iocp_socket_service_base::base_implementation_type& impl, boost::system::error_code& ec) { if (!is_open(impl)) { ec = boost::asio::error::bad_descriptor; return ec; } BOOST_ASIO_HANDLER_OPERATION((iocp_service_.context(), "socket", &impl, impl.socket_, "cancel")); if (FARPROC cancel_io_ex_ptr = ::GetProcAddress( ::GetModuleHandleA("KERNEL32"), "CancelIoEx")) { // The version of Windows supports cancellation from any thread. typedef BOOL (WINAPI* cancel_io_ex_t)(HANDLE, LPOVERLAPPED); cancel_io_ex_t cancel_io_ex = reinterpret_cast<cancel_io_ex_t>( reinterpret_cast<void*>(cancel_io_ex_ptr)); socket_type sock = impl.socket_; HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock); if (!cancel_io_ex(sock_as_handle, 0)) { DWORD last_error = ::GetLastError(); if (last_error == ERROR_NOT_FOUND) { // ERROR_NOT_FOUND means that there were no operations to be // cancelled. We swallow this error to match the behaviour on other // platforms. ec = boost::system::error_code(); } else { ec = boost::system::error_code(last_error, boost::asio::error::get_system_category()); } } else { ec = boost::system::error_code(); } } #if defined(BOOST_ASIO_ENABLE_CANCELIO) else if (impl.safe_cancellation_thread_id_ == 0) { // No operations have been started, so there's nothing to cancel. ec = boost::system::error_code(); } else if (impl.safe_cancellation_thread_id_ == ::GetCurrentThreadId()) { // Asynchronous operations have been started from the current thread only, // so it is safe to try to cancel them using CancelIo. socket_type sock = impl.socket_; HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock); if (!::CancelIo(sock_as_handle)) { DWORD last_error = ::GetLastError(); ec = boost::system::error_code(last_error, boost::asio::error::get_system_category()); } else { ec = boost::system::error_code(); } } else { // Asynchronous operations have been started from more than one thread, // so cancellation is not safe. ec = boost::asio::error::operation_not_supported; } #else // defined(BOOST_ASIO_ENABLE_CANCELIO) else { // Cancellation is not supported as CancelIo may not be used. ec = boost::asio::error::operation_not_supported; } #endif // defined(BOOST_ASIO_ENABLE_CANCELIO) // Cancel any operations started via the reactor. if (!ec) { select_reactor* r = static_cast<select_reactor*>( interlocked_compare_exchange_pointer( reinterpret_cast<void**>(&reactor_), 0, 0)); if (r) r->cancel_ops(impl.socket_, impl.reactor_data_); } return ec; } boost::system::error_code win_iocp_socket_service_base::do_open( win_iocp_socket_service_base::base_implementation_type& impl, int family, int type, int protocol, boost::system::error_code& ec) { if (is_open(impl)) { ec = boost::asio::error::already_open; return ec; } socket_holder sock(socket_ops::socket(family, type, protocol, ec)); if (sock.get() == invalid_socket) return ec; HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock.get()); if (iocp_service_.register_handle(sock_as_handle, ec)) return ec; impl.socket_ = sock.release(); switch (type) { case SOCK_STREAM: impl.state_ = socket_ops::stream_oriented; break; case SOCK_DGRAM: impl.state_ = socket_ops::datagram_oriented; break; default: impl.state_ = 0; break; } impl.cancel_token_.reset(static_cast<void*>(0), socket_ops::noop_deleter()); ec = boost::system::error_code(); return ec; } boost::system::error_code win_iocp_socket_service_base::do_assign( win_iocp_socket_service_base::base_implementation_type& impl, int type, socket_type native_socket, boost::system::error_code& ec) { if (is_open(impl)) { ec = boost::asio::error::already_open; return ec; } HANDLE sock_as_handle = reinterpret_cast<HANDLE>(native_socket); if (iocp_service_.register_handle(sock_as_handle, ec)) return ec; impl.socket_ = native_socket; switch (type) { case SOCK_STREAM: impl.state_ = socket_ops::stream_oriented; break; case SOCK_DGRAM: impl.state_ = socket_ops::datagram_oriented; break; default: impl.state_ = 0; break; } impl.cancel_token_.reset(static_cast<void*>(0), socket_ops::noop_deleter()); ec = boost::system::error_code(); return ec; } void win_iocp_socket_service_base::start_send_op( win_iocp_socket_service_base::base_implementation_type& impl, WSABUF* buffers, std::size_t buffer_count, socket_base::message_flags flags, bool noop, operation* op) { update_cancellation_thread_id(impl); iocp_service_.work_started(); if (noop) iocp_service_.on_completion(op); else if (!is_open(impl)) iocp_service_.on_completion(op, boost::asio::error::bad_descriptor); else { DWORD bytes_transferred = 0; int result = ::WSASend(impl.socket_, buffers, static_cast<DWORD>(buffer_count), &bytes_transferred, flags, op, 0); DWORD last_error = ::WSAGetLastError(); if (last_error == ERROR_PORT_UNREACHABLE) last_error = WSAECONNREFUSED; if (result != 0 && last_error != WSA_IO_PENDING) iocp_service_.on_completion(op, last_error, bytes_transferred); else iocp_service_.on_pending(op); } } void win_iocp_socket_service_base::start_send_to_op( win_iocp_socket_service_base::base_implementation_type& impl, WSABUF* buffers, std::size_t buffer_count, const void* addr, int addrlen, socket_base::message_flags flags, operation* op) { update_cancellation_thread_id(impl); iocp_service_.work_started(); if (!is_open(impl)) iocp_service_.on_completion(op, boost::asio::error::bad_descriptor); else { DWORD bytes_transferred = 0; int result = ::WSASendTo(impl.socket_, buffers, static_cast<DWORD>(buffer_count), &bytes_transferred, flags, static_cast<const socket_addr_type*>(addr), addrlen, op, 0); DWORD last_error = ::WSAGetLastError(); if (last_error == ERROR_PORT_UNREACHABLE) last_error = WSAECONNREFUSED; if (result != 0 && last_error != WSA_IO_PENDING) iocp_service_.on_completion(op, last_error, bytes_transferred); else iocp_service_.on_pending(op); } } void win_iocp_socket_service_base::start_receive_op( win_iocp_socket_service_base::base_implementation_type& impl, WSABUF* buffers, std::size_t buffer_count, socket_base::message_flags flags, bool noop, operation* op) { update_cancellation_thread_id(impl); iocp_service_.work_started(); if (noop) iocp_service_.on_completion(op); else if (!is_open(impl)) iocp_service_.on_completion(op, boost::asio::error::bad_descriptor); else { DWORD bytes_transferred = 0; DWORD recv_flags = flags; int result = ::WSARecv(impl.socket_, buffers, static_cast<DWORD>(buffer_count), &bytes_transferred, &recv_flags, op, 0); DWORD last_error = ::WSAGetLastError(); if (last_error == ERROR_NETNAME_DELETED) last_error = WSAECONNRESET; else if (last_error == ERROR_PORT_UNREACHABLE) last_error = WSAECONNREFUSED; if (result != 0 && last_error != WSA_IO_PENDING) iocp_service_.on_completion(op, last_error, bytes_transferred); else iocp_service_.on_pending(op); } } int win_iocp_socket_service_base::start_null_buffers_receive_op( win_iocp_socket_service_base::base_implementation_type& impl, socket_base::message_flags flags, reactor_op* op, operation* iocp_op) { if ((impl.state_ & socket_ops::stream_oriented) != 0) { // For stream sockets on Windows, we may issue a 0-byte overlapped // WSARecv to wait until there is data available on the socket. ::WSABUF buf = { 0, 0 }; start_receive_op(impl, &buf, 1, flags, false, iocp_op); return -1; } else { int op_type = (flags & socket_base::message_out_of_band) ? select_reactor::except_op : select_reactor::read_op; start_reactor_op(impl, op_type, op); return op_type; } } void win_iocp_socket_service_base::start_receive_from_op( win_iocp_socket_service_base::base_implementation_type& impl, WSABUF* buffers, std::size_t buffer_count, void* addr, socket_base::message_flags flags, int* addrlen, operation* op) { update_cancellation_thread_id(impl); iocp_service_.work_started(); if (!is_open(impl)) iocp_service_.on_completion(op, boost::asio::error::bad_descriptor); else { DWORD bytes_transferred = 0; DWORD recv_flags = flags; int result = ::WSARecvFrom(impl.socket_, buffers, static_cast<DWORD>(buffer_count), &bytes_transferred, &recv_flags, static_cast<socket_addr_type*>(addr), addrlen, op, 0); DWORD last_error = ::WSAGetLastError(); if (last_error == ERROR_PORT_UNREACHABLE) last_error = WSAECONNREFUSED; if (result != 0 && last_error != WSA_IO_PENDING) iocp_service_.on_completion(op, last_error, bytes_transferred); else iocp_service_.on_pending(op); } } void win_iocp_socket_service_base::start_accept_op( win_iocp_socket_service_base::base_implementation_type& impl, bool peer_is_open, socket_holder& new_socket, int family, int type, int protocol, void* output_buffer, DWORD address_length, operation* op) { update_cancellation_thread_id(impl); iocp_service_.work_started(); if (!is_open(impl)) iocp_service_.on_completion(op, boost::asio::error::bad_descriptor); else if (peer_is_open) iocp_service_.on_completion(op, boost::asio::error::already_open); else { boost::system::error_code ec; new_socket.reset(socket_ops::socket(family, type, protocol, ec)); if (new_socket.get() == invalid_socket) iocp_service_.on_completion(op, ec); else { DWORD bytes_read = 0; BOOL result = ::AcceptEx(impl.socket_, new_socket.get(), output_buffer, 0, address_length, address_length, &bytes_read, op); DWORD last_error = ::WSAGetLastError(); if (!result && last_error != WSA_IO_PENDING) iocp_service_.on_completion(op, last_error); else iocp_service_.on_pending(op); } } } void win_iocp_socket_service_base::restart_accept_op( socket_type s, socket_holder& new_socket, int family, int type, int protocol, void* output_buffer, DWORD address_length, long* cancel_requested, operation* op) { new_socket.reset(); iocp_service_.work_started(); // Check if we were cancelled after the first AcceptEx completed. if (cancel_requested) if (::InterlockedExchangeAdd(cancel_requested, 0) == 1) iocp_service_.on_completion(op, boost::asio::error::operation_aborted); boost::system::error_code ec; new_socket.reset(socket_ops::socket(family, type, protocol, ec)); if (new_socket.get() == invalid_socket) iocp_service_.on_completion(op, ec); else { DWORD bytes_read = 0; BOOL result = ::AcceptEx(s, new_socket.get(), output_buffer, 0, address_length, address_length, &bytes_read, op); DWORD last_error = ::WSAGetLastError(); if (!result && last_error != WSA_IO_PENDING) iocp_service_.on_completion(op, last_error); else { #if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0600) if (cancel_requested) { if (::InterlockedExchangeAdd(cancel_requested, 0) == 1) { HANDLE sock_as_handle = reinterpret_cast<HANDLE>(s); ::CancelIoEx(sock_as_handle, op); } } #endif // defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0600) iocp_service_.on_pending(op); } } } void win_iocp_socket_service_base::start_reactor_op( win_iocp_socket_service_base::base_implementation_type& impl, int op_type, reactor_op* op) { select_reactor& r = get_reactor(); update_cancellation_thread_id(impl); if (is_open(impl)) { r.start_op(op_type, impl.socket_, impl.reactor_data_, op, false, false); return; } else op->ec_ = boost::asio::error::bad_descriptor; iocp_service_.post_immediate_completion(op, false); } int win_iocp_socket_service_base::start_connect_op( win_iocp_socket_service_base::base_implementation_type& impl, int family, int type, const void* addr, std::size_t addrlen, win_iocp_socket_connect_op_base* op, operation* iocp_op) { // If ConnectEx is available, use that. if (family == BOOST_ASIO_OS_DEF(AF_INET) || family == BOOST_ASIO_OS_DEF(AF_INET6)) { if (connect_ex_fn connect_ex = get_connect_ex(impl, type)) { union address_union { socket_addr_type base; sockaddr_in4_type v4; sockaddr_in6_type v6; } a; using namespace std; // For memset. memset(&a, 0, sizeof(a)); a.base.sa_family = family; socket_ops::bind(impl.socket_, &a.base, family == BOOST_ASIO_OS_DEF(AF_INET) ? sizeof(a.v4) : sizeof(a.v6), op->ec_); if (op->ec_ && op->ec_ != boost::asio::error::invalid_argument) { iocp_service_.post_immediate_completion(op, false); return -1; } op->connect_ex_ = true; update_cancellation_thread_id(impl); iocp_service_.work_started(); BOOL result = connect_ex(impl.socket_, static_cast<const socket_addr_type*>(addr), static_cast<int>(addrlen), 0, 0, 0, iocp_op); DWORD last_error = ::WSAGetLastError(); if (!result && last_error != WSA_IO_PENDING) iocp_service_.on_completion(iocp_op, last_error); else iocp_service_.on_pending(iocp_op); return -1; } } // Otherwise, fall back to a reactor-based implementation. select_reactor& r = get_reactor(); update_cancellation_thread_id(impl); if ((impl.state_ & socket_ops::non_blocking) != 0 || socket_ops::set_internal_non_blocking( impl.socket_, impl.state_, true, op->ec_)) { if (socket_ops::connect(impl.socket_, addr, addrlen, op->ec_) != 0) { if (op->ec_ == boost::asio::error::in_progress || op->ec_ == boost::asio::error::would_block) { op->ec_ = boost::system::error_code(); r.start_op(select_reactor::connect_op, impl.socket_, impl.reactor_data_, op, false, false); return select_reactor::connect_op; } } } r.post_immediate_completion(op, false); return -1; } void win_iocp_socket_service_base::close_for_destruction( win_iocp_socket_service_base::base_implementation_type& impl) { if (is_open(impl)) { BOOST_ASIO_HANDLER_OPERATION((iocp_service_.context(), "socket", &impl, impl.socket_, "close")); // Check if the reactor was created, in which case we need to close the // socket on the reactor as well to cancel any operations that might be // running there. select_reactor* r = static_cast<select_reactor*>( interlocked_compare_exchange_pointer( reinterpret_cast<void**>(&reactor_), 0, 0)); if (r) r->deregister_descriptor(impl.socket_, impl.reactor_data_, true); boost::system::error_code ignored_ec; socket_ops::close(impl.socket_, impl.state_, true, ignored_ec); if (r) r->cleanup_descriptor_data(impl.reactor_data_); } impl.socket_ = invalid_socket; impl.state_ = 0; impl.cancel_token_.reset(); #if defined(BOOST_ASIO_ENABLE_CANCELIO) impl.safe_cancellation_thread_id_ = 0; #endif // defined(BOOST_ASIO_ENABLE_CANCELIO) } void win_iocp_socket_service_base::update_cancellation_thread_id( win_iocp_socket_service_base::base_implementation_type& impl) { #if defined(BOOST_ASIO_ENABLE_CANCELIO) if (impl.safe_cancellation_thread_id_ == 0) impl.safe_cancellation_thread_id_ = ::GetCurrentThreadId(); else if (impl.safe_cancellation_thread_id_ != ::GetCurrentThreadId()) impl.safe_cancellation_thread_id_ = ~DWORD(0); #else // defined(BOOST_ASIO_ENABLE_CANCELIO) (void)impl; #endif // defined(BOOST_ASIO_ENABLE_CANCELIO) } select_reactor& win_iocp_socket_service_base::get_reactor() { select_reactor* r = static_cast<select_reactor*>( interlocked_compare_exchange_pointer( reinterpret_cast<void**>(&reactor_), 0, 0)); if (!r) { r = &(use_service<select_reactor>(context_)); interlocked_exchange_pointer(reinterpret_cast<void**>(&reactor_), r); } return *r; } win_iocp_socket_service_base::connect_ex_fn win_iocp_socket_service_base::get_connect_ex( win_iocp_socket_service_base::base_implementation_type& impl, int type) { #if defined(BOOST_ASIO_DISABLE_CONNECTEX) (void)impl; (void)type; return 0; #else // defined(BOOST_ASIO_DISABLE_CONNECTEX) if (type != BOOST_ASIO_OS_DEF(SOCK_STREAM) && type != BOOST_ASIO_OS_DEF(SOCK_SEQPACKET)) return 0; void* ptr = interlocked_compare_exchange_pointer(&connect_ex_, 0, 0); if (!ptr) { GUID guid = { 0x25a207b9, 0xddf3, 0x4660, { 0x8e, 0xe9, 0x76, 0xe5, 0x8c, 0x74, 0x06, 0x3e } }; DWORD bytes = 0; if (::WSAIoctl(impl.socket_, SIO_GET_EXTENSION_FUNCTION_POINTER, &guid, sizeof(guid), &ptr, sizeof(ptr), &bytes, 0, 0) != 0) { // Set connect_ex_ to a special value to indicate that ConnectEx is // unavailable. That way we won't bother trying to look it up again. ptr = this; } interlocked_exchange_pointer(&connect_ex_, ptr); } return reinterpret_cast<connect_ex_fn>(ptr == this ? 0 : ptr); #endif // defined(BOOST_ASIO_DISABLE_CONNECTEX) } win_iocp_socket_service_base::nt_set_info_fn win_iocp_socket_service_base::get_nt_set_info() { void* ptr = interlocked_compare_exchange_pointer(&nt_set_info_, 0, 0); if (!ptr) { if (HMODULE h = ::GetModuleHandleA("NTDLL.DLL")) ptr = reinterpret_cast<void*>(GetProcAddress(h, "NtSetInformationFile")); // On failure, set nt_set_info_ to a special value to indicate that the // NtSetInformationFile function is unavailable. That way we won't bother // trying to look it up again. interlocked_exchange_pointer(&nt_set_info_, ptr ? ptr : this); } return reinterpret_cast<nt_set_info_fn>(ptr == this ? 0 : ptr); } void* win_iocp_socket_service_base::interlocked_compare_exchange_pointer( void** dest, void* exch, void* cmp) { #if defined(_M_IX86) return reinterpret_cast<void*>(InterlockedCompareExchange( reinterpret_cast<PLONG>(dest), reinterpret_cast<LONG>(exch), reinterpret_cast<LONG>(cmp))); #else return InterlockedCompareExchangePointer(dest, exch, cmp); #endif } void* win_iocp_socket_service_base::interlocked_exchange_pointer( void** dest, void* val) { #if defined(_M_IX86) return reinterpret_cast<void*>(InterlockedExchange( reinterpret_cast<PLONG>(dest), reinterpret_cast<LONG>(val))); #else return InterlockedExchangePointer(dest, val); #endif } } // namespace detail } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // defined(BOOST_ASIO_HAS_IOCP) #endif // BOOST_ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP