mirrors/ugv_sdk
1
0
Fork 0
mirror of https://github.com/westonrobot/ugv_sdk synced 2023-04-08 06:32:14 +08:00
Code Issues Packages Projects Releases Wiki Activity
Files
4c729c9cac0558e364c88b83ac48bc6b5900738b
ugv_sdk/asio/doc/asio/history.html
Ruixiang Du 6914169386 moved asio folder and tested catkin-isolated build
2020-09-14 16:34:39 +08:00

3000 lines
153 KiB
HTML
Raw Blame History

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Revision History</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<link rel="home" href="../index.html" title="Asio">
<link rel="up" href="../index.html" title="Asio">
<link rel="prev" href="std_executors.html" title="Proposed Standard Executors">
<link rel="next" href="index.html" title="">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="asio C++ library" width="250" height="60" src="../asio.png"></td></tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="std_executors.html"><img src="../prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../home.png" alt="Home"></a><a accesskey="n" href="index.html"><img src="../next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="asio.history"></a><a class="link" href="history.html" title="Revision History">Revision History</a>
</h2></div></div></div>
<h4>
<a name="asio.history.h0"></a>
<span><a name="asio.history.asio_1_18_0"></a></span><a class="link" href="history.html#asio.history.asio_1_18_0">Asio
1.18.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Marked the <code class="computeroutput">basic_socket_acceptor</code> move constructor as <code class="computeroutput">noexcept</code>.
</li>
<li class="listitem">
Added workarounds for various issues in <code class="literal">gcc</code> 10's coroutine
support.
</li>
<li class="listitem">
Added standard executor support to <code class="computeroutput">windows::overlapped_ptr</code>.
</li>
<li class="listitem">
Added missing compatibility macros for the <code class="computeroutput">execution::receiver_of</code>
concept.
</li>
<li class="listitem">
Added short-circuited evaluation to <code class="computeroutput">execution::executor</code>,
<code class="computeroutput">execution::operation_state</code>,<code class="computeroutput">execution::sender</code>,
<code class="computeroutput">execution::receiver</code>, <code class="computeroutput">execution::receiver_of</code>,
and <code class="computeroutput">execution::scheduler</code> concepts and the corresponding traits.
These now test first for well-formed CPO expressions (or, in the case of
senders, a specialised <code class="computeroutput">sender_traits</code> template) and, if not
valid, short-circuit the remainder of the evaluation. This helps prevent
recursive template instantiations that can occur in some contexts.
</li>
<li class="listitem">
Added constraints to the <code class="computeroutput">strand</code> template's constructor, to
prevent template instantiation recursion.
</li>
<li class="listitem">
Changed Asio's internal executor adapters to prevent template instantiation
recursion.
</li>
<li class="listitem">
Added constraints to the <code class="computeroutput">execution::any_executor</code> template's
converting constructors, as per the specification.
</li>
<li class="listitem">
Added missing <code class="computeroutput">execution::sender_traits</code> specialisation and
<code class="computeroutput">connect()</code> member function to the <code class="computeroutput">thread_pool</code>
executor, as per the specification.
</li>
<li class="listitem">
Changed <code class="computeroutput">execution::blocking_t::always_t::is_preferable</code> to
be false as per the specification.
</li>
<li class="listitem">
Added <code class="computeroutput">shape_type</code> and <code class="computeroutput">index_type</code> to <code class="computeroutput">thread_pool</code>
executors, as per the specification.
</li>
<li class="listitem">
Ensured that the standard executor concept-related traits (such as <code class="computeroutput">execution::is_executor</code>)
work with <code class="computeroutput">void</code>.
</li>
<li class="listitem">
Fixed <code class="computeroutput">async_compose</code> support for standard executors.
</li>
<li class="listitem">
Fixed the forward declaration of <code class="computeroutput">any_io_executor</code> in <code class="literal">asio/ts/netfwd.hpp</code>.
</li>
<li class="listitem">
Fixed <code class="computeroutput">use_future</code> compatibility with older compilers.
</li>
<li class="listitem">
Fixed compatibility with MinGW.
</li>
<li class="listitem">
Improved compatibility with older versions of <code class="literal">gcc</code>.
</li>
<li class="listitem">
Added compatiblity with <code class="literal">clang-cl</code> on Windows.
</li>
<li class="listitem">
Fixed various compiler warnings.
</li>
<li class="listitem">
Added basic overview documentation for the standard executors support.
</li>
<li class="listitem">
Added detailed descriptions to the standard executor-related member functions
of <code class="computeroutput">io_context</code> executors, <code class="computeroutput">thread_pool</code> executors,
<code class="computeroutput">system_executor</code>, and <code class="computeroutput">strand&lt;&gt;</code>.
</li>
<li class="listitem">
Changed introductory documentation to reflect that there our now multiple
types of I/O execution context.
</li>
<li class="listitem">
Marked constructors, destructors, and static data members in class synopses
in the reference documentation.
</li>
<li class="listitem">
Fixed various minor documentation errors.
</li>
</ul></div>
<h4>
<a name="asio.history.h1"></a>
<span><a name="asio.history.asio_1_17_0"></a></span><a class="link" href="history.html#asio.history.asio_1_17_0">Asio
1.17.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added an implementation of the proposed standard executors (<a href="http://wg21.link/P0443r13" target="_top">P0443r13</a>,
<a href="http://wg21.link/P1348r0" target="_top">P1348r0</a>, and <a href="http://wg21.link/P1393r0" target="_top">P1393r0</a>).
</li>
<li class="listitem">
Added support for the proposed standard executors to Asio's I/O facilities:
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
The <code class="computeroutput">io_context::executor_type</code>, <code class="computeroutput">thread_pool::executor_type</code>,
<code class="computeroutput">system_executor</code>, and <code class="computeroutput">strand</code> executors now
meet the requirements for the proposed standard executors. These
classes also continue to meet the existing requirements for the Networking
TS model of executors.
</li>
<li class="listitem">
All I/O objects, asynchronous operations, and utilities including
<code class="computeroutput">dispatch</code>, <code class="computeroutput">post</code>, <code class="computeroutput">defer</code>, <code class="computeroutput">get_associated_executor</code>,
<code class="computeroutput">bind_executor</code>, <code class="computeroutput">make_work_guard</code>, <code class="computeroutput">spawn</code>,
<code class="computeroutput">co_spawn</code>, <code class="computeroutput">async_compose</code>, <code class="computeroutput">use_future</code>,
etc., can interoperate with both new proposed standard executors,
and with existing Networking TS executors. The implementation determines
at compile time which model a particular executor meets; the proposed
standard executor model is used in preference if both are detected.
</li>
<li class="listitem">
The <code class="computeroutput">any_io_executor</code> type alias has been introduced as
the new default runtime-polymorphic executor for all I/O objects.
This type alias points to the <code class="computeroutput">execution::any_executor&lt;&gt;</code>
template with a set of supportable properties specified for use with
I/O. This change may break existing code that directly uses the old
polymorphic wrapper, <code class="computeroutput">executor</code>. If required for backward
compatibility, <code class="computeroutput">ASIO_USE_TS_EXECUTOR_AS_DEFAULT</code> can be
defined, which changes the <code class="computeroutput">any_io_executor</code> type alias
to instead point to the <code class="computeroutput">executor</code> polymorphic wrapper.
</li>
<li class="listitem">
Support for the existing Networking TS model of executors can be
disabled by defining <code class="computeroutput">ASIO_NO_TS_EXECUTORS</code>.
</li>
</ul></div>
</li>
<li class="listitem">
Added converting move construction and assignment to <code class="computeroutput">basic_waitable_timer</code>.
This enables move construction and assignment between different timer types,
provided the executor types are convertible. For example:<br>
<pre class="programlisting">basic_waitable_timer&lt;
clock_type,
traits_type,
io_context::executor_type
&gt; timer1(my_io_context);
basic_waitable_timer&lt;
clock_type,
traits_type,
any_io_executor // polymorphic wrapper
&gt; timer2(std::move(timer1));
</pre>
<br>
</li>
<li class="listitem">
Enabled C++20 coroutine support when using <code class="literal">gcc</code> 10.
</li>
<li class="listitem">
Added overloads of <code class="computeroutput">co_spawn</code> that launch an awaitable. This
change allows us to write:<br>
<pre class="programlisting">co_spawn(executor,
echo(std::move(socket)),
detached);
</pre>
<br> instead of:<br>
<pre class="programlisting">co_spawn(executor,
[socket = std::move(socket)]() mutable
{
return echo(std::move(socket));
},
detached);
</pre>
<br>
</li>
<li class="listitem">
Added a new constructor overload to <code class="computeroutput">use_awaitable_t</code>'s default
executor adapter, to enable conversion between executor types.
</li>
<li class="listitem">
Added support for using <code class="computeroutput">detached_t</code> as a default completion
token, by adding members <code class="computeroutput">as_default_on()</code> and <code class="computeroutput">as_default_on_t&lt;&gt;</code>.
</li>
<li class="listitem">
Added a move constructor to <code class="computeroutput">ssl::stream&lt;&gt;</code>.
</li>
<li class="listitem">
Changed <code class="computeroutput">ssl::stream&lt;&gt;</code> write operations to linearise
gather-write buffer sequences.
</li>
<li class="listitem">
Added compile-time detection of the deprecated <code class="computeroutput">asio_handler_invoke</code>
hook. This hook was deprecated with the introduction of the Networking
TS trait <code class="computeroutput">associated_executor</code> and function <code class="computeroutput">get_associated_executor()</code>.
Compiling an application with <code class="computeroutput">ASIO_NO_DEPRECATED</code> will now
trigger a compile error if any handler implements the <code class="computeroutput">asio_handler_invoke</code>
hook.
</li>
<li class="listitem">
Added compile-time detection of the deprecated <code class="computeroutput">asio_handler_allocate</code>
and <code class="computeroutput">asio_handle_deallocate</code> hooks. These hooks were deprecated
with the introduction of the Networking TS trait <code class="computeroutput">associated_allocator</code>
and function <code class="computeroutput">get_associated_allocator()</code>. Compiling an application
with <code class="computeroutput">ASIO_NO_DEPRECATED</code> will now trigger a compile error if
any handler implements the <code class="computeroutput">asio_handler_allocate</code> or <code class="computeroutput">asio_handler_deallocate</code>
hooks.
</li>
<li class="listitem">
Implemented a number of performance optimisations, including:
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Specialising single-buffer operations to use <code class="computeroutput">recv</code> rather
than <code class="computeroutput">recvmsg</code>, <code class="computeroutput">send</code> rather than <code class="computeroutput">sendmsg</code>,
<code class="computeroutput">read</code> rather than <code class="computeroutput">readv</code>, and <code class="computeroutput">write</code>
rather than <code class="computeroutput">writev</code>.
</li>
<li class="listitem">
Lightening the reference counting overhead of the polymorphic wrapper
<code class="computeroutput">executor</code>.
</li>
<li class="listitem">
Returning from system call operation wrappers as early as possible,
and only accessing <code class="computeroutput">errno</code> and error codes when on an
error path.
</li>
<li class="listitem">
Applying additional optimisations if a "native" I/O executor
(such as <code class="computeroutput">io_context::exeutor_type</code>) is detected.
</li>
</ul></div>
</li>
<li class="listitem">
Added source location support to handler tracking. The new <code class="computeroutput">ASIO_HANDLER_LOCATION((file_name,
line, function_name))</code> macro may be used to inform the handler tracking
mechanism of a source location. This macro declares an object that is placed
on the stack. Then, when an asynchronous operation is launched with location
information, it outputs lines using the <span class="bold"><strong>&lt;action&gt;</strong></span>
<code class="literal">n^m</code>, prior to the <code class="literal">n*m</code> line that signifies
the beginning of the asynchronous operation. For example:
<pre class="programlisting">@asio|1589423304.861944|&gt;7|ec=system:0,bytes_transferred=5
@asio|1589423304.861952|7^8|in 'async_write' (./../../../include/asio/impl/write.hpp:330)
@asio|1589423304.861952|7^8|called from 'do_write' (handler_tracking/async_tcp_echo_server.cpp:62)
@asio|1589423304.861952|7^8|called from 'operator()' (handler_tracking/async_tcp_echo_server.cpp:51)
@asio|1589423304.861952|7*8|socket@0x7ff61c008230.async_send
@asio|1589423304.861975|.8|non_blocking_send,ec=system:0,bytes_transferred=5
@asio|1589423304.861980|&lt;7|
</pre>
<br> If <code class="computeroutput">std::source_location</code> or <code class="computeroutput">std::experimental::source_location</code>
are available, the <code class="computeroutput">use_awaitable_t</code> token (when default-constructed
or used as a default completion token) will also cause handler tracking
to output a source location for each newly created asynchronous operation.
A <code class="computeroutput">use_awaitable_t</code> object may also be explicitly constructed
with location information.
</li>
<li class="listitem">
Implemented various improvements to the <code class="literal">handlerviz.pl</code>
tool.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Add nodes for pending handlers at bottom of graph, outlined in red.
</li>
<li class="listitem">
Display source location in a tooltip on the edge label (for SVG).
</li>
<li class="listitem">
Use invisible nodes to enforce order to keep related control flow
vertical.
</li>
</ul></div>
</li>
<li class="listitem">
Added the <code class="literal">handlerlive.pl</code> tool, which processes handler
tracking output to produce a list of "live" handlers. Live handlers
are those that are associated with pending asynchronous operations, as
well as handlers that are currently executing. For example:
<pre class="programlisting">cat output.txt | perl handlerlive.pl
</pre>
or:
<pre class="programlisting">perl handerlive.pl &lt; output.txt
</pre>
or:
<pre class="programlisting">perl handlerlive.pl output.txt
</pre>
<br>
</li>
<li class="listitem">
Added the <code class="literal">handlertree.pl</code> tool, which filters handler
tracking output to include only those events in the tree that produced
the nominated handlers. For example, to filter the output to include only
the events associated with handlers <code class="computeroutput">123</code>, <code class="computeroutput">456</code>,
and their predecessors:
<pre class="programlisting">cat output.txt | perl handlertree.pl 123 456
</pre>
or:
<pre class="programlisting">perl handlertree.pl 123 456 &lt; output.txt
</pre>
<br> This script may be combined with handerlive.pl and handlerviz.pl
to produce a graph of the "live" asynchronous operation chains.
For example:
<pre class="programlisting">cat output.txt | \
perl handlertree.pl `perl handlerlive.pl output.txt` | \
perl handlerviz.pl | \
dot -Tsvg &gt; output.svg
</pre>
<br>
</li>
<li class="listitem">
Added changes for clang-based Embarcadero C++ compilers.
</li>
<li class="listitem">
Fixed a deadlock that can occur when multiple threads concurrently initialise
the Windows I/O completion port backend.
</li>
<li class="listitem">
Fixed <code class="computeroutput">async_compose</code> to work with copyable handlers when passed
by lvalue.
</li>
<li class="listitem">
Fixed completion signature deduction in <code class="computeroutput">co_spawn</code>.
</li>
<li class="listitem">
Removed a spurious <code class="computeroutput">Executor</code> base class from the <code class="computeroutput">executor_binder</code>
implementation.
</li>
<li class="listitem">
Various fixes and improvements in the documentation and examples.
</li>
</ul></div>
<h4>
<a name="asio.history.h2"></a>
<span><a name="asio.history.asio_1_16_1"></a></span><a class="link" href="history.html#asio.history.asio_1_16_1">Asio
1.16.1</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Fixed compatibility with C++20 concept syntax.
</li>
<li class="listitem">
Marked the POSIX descriptor classes' move constructors as <code class="computeroutput">noexcept</code>.
</li>
<li class="listitem">
Added the <code class="computeroutput">ssl::host_name_verification</code> class, which is a drop-in
replacement for <code class="computeroutput">ssl::rfc2818_verification</code>. The <code class="computeroutput">ssl::rfc2818_verification</code>
class has been marked as deprecated. As a consequence of this change, SSL
support now depends on functions that were introduced in OpenSSL 1.0.2.
</li>
<li class="listitem">
Added an <code class="computeroutput">ssl::context</code> constructor to take ownership of a native
handle.
</li>
<li class="listitem">
Changed C++ language version detection with <code class="literal">gcc</code> to use
<code class="computeroutput">__cplusplus</code> macro.
</li>
<li class="listitem">
Fixed a work counting issue in the asynchronous resolve operation for endpoints.
</li>
<li class="listitem">
Fixed the <code class="computeroutput">strand&lt;&gt;</code> converting constructors and assignment
operators.
</li>
<li class="listitem">
Ensured that resolvers are restarted correctly after a fork.
</li>
<li class="listitem">
Fixed compatibility with the current NetBSD release.
</li>
<li class="listitem">
Removed spurious handler requirement checks in some <code class="computeroutput">async_read</code>
overloads.
</li>
<li class="listitem">
Changed the <code class="computeroutput">ssl::context</code> class to propagate non-EOF errors
from the <code class="computeroutput">add_certificate_authority</code> function.
</li>
<li class="listitem">
Fixed a Windows-specific <code class="computeroutput">thread_pool</code> destructor hang that
occurred when the pool had an associated I/O object.
</li>
<li class="listitem">
Changed the <code class="literal">select</code> reactor to recreate the "self
pipe trick" sockets on error. This addresses an issue on some versions
of Windows, where these sockets are discconected after a system sleep.
</li>
<li class="listitem">
Fixed a compile error in the buffered streams due to the lack of reference
collapsing in C++98.
</li>
<li class="listitem">
Changed the <code class="computeroutput">priority_scheduler</code> example to demonstrate calls
to <code class="computeroutput">shutdown()</code> and <code class="computeroutput">destroy()</code>.
</li>
<li class="listitem">
Removed some unnecessary null pointer checks.
</li>
<li class="listitem">
Changed Windows platform detection to recognise TV titles as Windows apps.
</li>
<li class="listitem">
Added some emscripten compatibility patches.
</li>
<li class="listitem">
Fixed a compile error in the <code class="computeroutput">use_awaitable_t::as_default_on</code>
function.
</li>
<li class="listitem">
Changed all uses of the boost.bind placeholders to use the <code class="computeroutput">boost::placeholders</code>
namespace.
</li>
<li class="listitem">
Fixed a potential compile error in the <code class="computeroutput">async_compose</code> implementation
due to incorrect overload selection.
</li>
<li class="listitem">
Suppressed some non-virtual destructor warnings.
</li>
<li class="listitem">
Various documentation fixes and improvements.
</li>
</ul></div>
<h4>
<a name="asio.history.h3"></a>
<span><a name="asio.history.asio_1_16_0"></a></span><a class="link" href="history.html#asio.history.asio_1_16_0">Asio
1.16.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Changed the <code class="computeroutput">async_initiate</code> helper function to automatically
deduce its return type. This is enabled for C++11 or later.
</li>
<li class="listitem">
Changed all asynchronous operations to use automatically deduced return
types. This allows completion token implementations to incorporate the
asynchronous operation initiation into the initiating function's return
type, without type erasure. Note that C++14 or later is required to support
completion tokens that use per-operation return type deduction. For C++11
or earlier, a completion token's async_result specialisation must still
provide the nested typedef <code class="computeroutput">return_type</code>.
</li>
<li class="listitem">
Introduced three new concepts to support <code class="computeroutput">async_initiate</code>.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
<code class="computeroutput">completion_signature&lt;T&gt;</code>: Checks if <code class="computeroutput">T</code>
is a signature of the form <code class="computeroutput">R(Args...)</code>.
</li>
<li class="listitem">
<code class="computeroutput">completion_handler_for&lt;T, Signature&gt;</code>: Checks if
<code class="computeroutput">T</code> is usable as a completion handler with the specified
signature.
</li>
<li class="listitem">
<code class="computeroutput">completion_token_for&lt;T, Signature&gt;</code>: Checks if
<code class="computeroutput">T</code> is a completion token that can be used with async_initiate
and the specified signature.
</li>
<li class="listitem">
For backward compatibility with pre-concepts C++, the macros <code class="computeroutput">(BOOST_)ASIO_COMPLETION_SIGNATURE</code>,
<code class="computeroutput">(BOOST_)ASIO_COMPLETION_HANDLER_FOR</code>, and <code class="computeroutput">(BOOST_)ASIO_COMPLETION_TOKEN_FOR</code>
are provided. These macros expand to <code class="computeroutput">typename</code> when concepts
are unsupported.
</li>
</ul></div>
</li>
<li class="listitem">
Added the nested template type <code class="computeroutput">rebind_executor</code> to all I/O
object types, as a way to generically rebind them to use alternative I/O
executors. For example:
<pre class="programlisting">using my_socket_type = tcp::socket::rebind_executor&lt;my_executor_type&gt;::other;
</pre>
<br>
</li>
<li class="listitem">
Changed the asynchronous operations' initiation function objects to report
their associated I/O executor via the nested type <code class="computeroutput">executor_type</code>
and member function <code class="computeroutput">get_executor()</code>. Note that the presence
of <code class="computeroutput">executor_type</code> and <code class="computeroutput">get_executor()</code> should be
treated as optional, and consequently it may be preferable to access them
via the <code class="computeroutput">associated_executor</code> trait and the <code class="computeroutput">get_associated_executor()</code>
helper function.
</li>
<li class="listitem">
Added the <code class="computeroutput">default_completion_token</code> trait, so that every I/O
executor type now has an associated default completion token type. This
trait may be used in asynchronous operation declarations as follows:
<pre class="programlisting">template &lt;
typename IoObject,
typename CompletionToken =
typename default_completion_token&lt;
typename IoObject::executor_type
&gt;::type
&gt;
auto async_xyz(
IoObject&amp; io_object,
CompletionToken&amp;&amp; token =
typename default_completion_token&lt;
typename IoObject::executor_type
&gt;::type{}
);
</pre>
<br> If not specialised, this trait type is <code class="computeroutput">void</code>, meaning
no default completion token type is available for the given I/O executor.
</li>
<li class="listitem">
Specialised the <code class="computeroutput">default_completion_token</code> trait for the <code class="computeroutput">use_awaitable</code>
completion token, so that it may be used as shown in the following example:
<pre class="programlisting">auto socket = use_awaitable.as_default_on(tcp::socket(my_context));
// ...
co_await socket.async_connect(my_endpoint); // Defaults to use_awaitable.
</pre>
<br> In this example, the type of the <code class="computeroutput">socket</code> object is transformed
from <code class="computeroutput">tcp::socket</code> to have an I/O executor with the default
completion token set to <code class="computeroutput">use_awaitable</code>. Alternatively, the
socket type may be computed directly:
<pre class="programlisting">using tcp_socket = use_awaitable_t&lt;&gt;::as_default_on_t&lt;tcp::socket&gt;;
tcp_socket socket(my_context);
// ...
co_await socket.async_connect(my_endpoint); // Defaults to use_awaitable.
</pre>
<br>
</li>
<li class="listitem">
Added missing <code class="computeroutput">async_initiate</code> to the Windows-specific I/O objects'
asynchronous operations.
</li>
<li class="listitem">
Ensured that the executor type is propagated to newly accepted sockets.
When synchronously or asynchronously accepting a new connection, but without
specifying an executor or execution context, the accept operation will
now correctly propagate the executor type from the acceptor to the socket.
For example, if your acceptor type is:
<pre class="programlisting">basic_socket_acceptor&lt;ip::tcp, my_executor_type&gt;
</pre>
<br> then your accepted socket type will be:
<pre class="programlisting">basic_stream_socket&lt;ip::tcp, my_executor_type&gt;
</pre>
<br>
</li>
<li class="listitem">
Changed to require that <code class="computeroutput">Protocol</code> copy and move operations
never throw.
</li>
<li class="listitem">
Changed to require that <code class="computeroutput">Endpoint</code> default constructor and move
operations never throw.
</li>
<li class="listitem">
Added the <code class="computeroutput">noexcept</code> qualifier to protocol accessors.
</li>
<li class="listitem">
Added the <code class="computeroutput">noexcept</code> qualifier to socket move constructors.
</li>
<li class="listitem">
Fixed issues associated with opening serial ports on Windows:
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Use the correct constant to initialise the RTS control flag.
</li>
<li class="listitem">
Specify a default baud rate (9600).
</li>
</ul></div>
</li>
<li class="listitem">
Fixed a lost "outstanding work count" that can occur when an
asynchronous accept operation is automatically restarted.
</li>
</ul></div>
<h4>
<a name="asio.history.h4"></a>
<span><a name="asio.history.asio_1_14_1"></a></span><a class="link" href="history.html#asio.history.asio_1_14_1">Asio
1.14.1</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Improved performance slightly by eliminating a redundant move construction
when completed handlers are dispatched.
</li>
<li class="listitem">
Eliminated a compiler warning by annotating a <code class="computeroutput">case</code> fall-through
in the free function <code class="computeroutput">connect()</code> implementation.
</li>
<li class="listitem">
Fixed the <code class="computeroutput">is_*_buffer_sequence</code> detection traits for user-defined
sequence types.
</li>
<li class="listitem">
Fixed some Windows-specific warnings about an incompatible pointer cast
when obtaining the <code class="computeroutput">CancelIoEx</code> entry point.
</li>
<li class="listitem">
Changed to automatically set the defaults when opening a serial port on
Windows.
</li>
<li class="listitem">
Changed the serial port <code class="computeroutput">get_option()</code> member function to be
const.
</li>
<li class="listitem">
Fixed a name hiding issue with the WinRT stream-oriented socket backend's
<code class="computeroutput">shutdown</code> function.
</li>
<li class="listitem">
Applied a minor fix to the documentation for <code class="computeroutput">is_dynamic_buffer</code>.
</li>
<li class="listitem">
Added some support for Haiku OS.
</li>
<li class="listitem">
Added wolfSSL compatability.
</li>
<li class="listitem">
Changed to require C++17 or later for coroutines TS support with clang.
</li>
<li class="listitem">
Fixed a doxygen generation problem in the tutorial.
</li>
</ul></div>
<h4>
<a name="asio.history.h5"></a>
<span><a name="asio.history.asio_1_14_0"></a></span><a class="link" href="history.html#asio.history.asio_1_14_0">Asio
1.14.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Improved I/O object performance by adding runtime detection of native I/O
executors when using the polymorphic executor wrapper.
</li>
<li class="listitem">
Changed I/O object move constructors so that the executor is copied, not
moved. This ensures that the moved-from I/O object is left in the same
state as if constructed with a valid executor but without a resource.
</li>
<li class="listitem">
On Windows, fixed an issue where global object destructors were not being
run.
</li>
<li class="listitem">
Fixed move-based <code class="computeroutput">async_accept</code> between sockets with different
executor types.
</li>
</ul></div>
<h4>
<a name="asio.history.h6"></a>
<span><a name="asio.history.asio_1_13_0"></a></span><a class="link" href="history.html#asio.history.asio_1_13_0">Asio
1.13.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added custom I/O executor support to I/O objects.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
All I/O objects now have an additional <code class="computeroutput">Executor</code> template
parameter. This template parameter defaults to the <code class="computeroutput">asio::executor</code>
type (the polymorphic executor wrapper) but can be used to specify
a user-defined executor type.
</li>
<li class="listitem">
I/O objects' constructors and functions that previously took an
<code class="computeroutput">asio::io_context&amp;</code> now accept either an <code class="computeroutput">Executor</code>
or a reference to a concrete <code class="computeroutput">ExecutionContext</code> (such
as <code class="computeroutput">asio::io_context</code> or <code class="computeroutput">asio::thread_pool</code>).
</li>
<li class="listitem">
Note: One potential source of breakage in existing user code is when
reusing an I/O object's <code class="computeroutput">io_context</code> for constructing
another I/O object, as in:
<pre class="programlisting">asio::steady_timer my_timer(my_socket.get_executor().context());
</pre>
<br> To fix this, either construct the second I/O object using
the first I/O object's executor:<br>
<pre class="programlisting">asio::steady_timer my_timer(my_socket.get_executor());
</pre>
<br> or otherwise explicitly pass the <code class="computeroutput">io_context</code>:<br>
<pre class="programlisting">asio::steady_timer my_timer(my_io_context);
</pre>
<br>
</li>
<li class="listitem">
The previously deprecated <code class="computeroutput">get_io_context</code> and <code class="computeroutput">get_io_service</code>
member functions have now been removed.
</li>
<li class="listitem">
The previously deprecated service template parameters, and the corresponding
classes, have now been removed.
</li>
</ul></div>
</li>
<li class="listitem">
Added a new <code class="computeroutput">async_result</code> form with an <code class="computeroutput">initiate</code>
static member function.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
The <code class="computeroutput">async_result</code> template now supports a new form:
<pre class="programlisting">template &lt;typename CompletionToken, typename Signature&gt;
struct async_result
{
typedef /* ... */ return_type;
template &lt;typename Initiation,
typename RawCompletionToken,
typename... Args&gt;
static return_type initiate(
Initiation&amp;&amp; initiation,
RawCompletionToken&amp;&amp; token,
Args&amp;&amp;... args);
};
</pre>
<br>
</li>
<li class="listitem">
The <code class="computeroutput">initiate</code> member function must: (a) transform the
token into a completion handler object <code class="computeroutput">handler</code>; (b)
cause the invocation of the function object <code class="computeroutput">initiation</code>
as if by calling <code class="computeroutput">std::forward&lt;Initiation&gt;(initiation)(std::move(handler),
std::forward&lt;Args&gt;(args)...)</code>. Note that the invocation
of <code class="computeroutput">initiation</code> may be deferred (e.g. lazily evaluated),
in which case <code class="computeroutput">initiation</code> and <code class="computeroutput">args</code> must
be decay-copied and moved as required.
</li>
<li class="listitem">
A helper function template <code class="computeroutput">async_initiate</code> has also been
added as a wrapper for the invocation of <code class="computeroutput">async_result&lt;&gt;::initiate</code>.
For backward compatibility, this function supports both the old and
new <code class="computeroutput">async_result</code> forms.
</li>
<li class="listitem">
The composed operations examples have been updated to use <code class="computeroutput">async_initiate</code>.
</li>
<li class="listitem">
The previously deprecated <code class="computeroutput">handler_type</code> trait and single-argument
form of <code class="computeroutput">async_result</code> have now been removed.
</li>
</ul></div>
</li>
<li class="listitem">
Updated the Coroutines TS support and promoted it to the <code class="computeroutput">asio</code>
namespace.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
The <code class="computeroutput">awaitable&lt;&gt;</code>, <code class="computeroutput">co_spawn</code>, <code class="computeroutput">this_coro</code>,
<code class="computeroutput">detached</code>, and <code class="computeroutput">redirect_error</code> facilities
have been moved from the <code class="computeroutput">asio::experimental</code> namespace
to namespace <code class="computeroutput">asio</code>. As part of this change, the <code class="computeroutput">this_coro::token()</code>
awaitable has been superseded by the <code class="computeroutput">asio::use_awaitable</code>
completion token.
</li>
<li class="listitem">
Please note that the <code class="computeroutput">use_awaitable</code> and <code class="computeroutput">redirect_error</code>
completion tokens work only with asynchronous operations that use
the new form of <code class="computeroutput">async_result</code> with member function <code class="computeroutput">initiate</code>.
Furthermore, when using <code class="computeroutput">use_awaitable</code>, please be aware
that the asynchronous operation is not initiated until <code class="computeroutput">co_await</code>
is applied to the <code class="computeroutput">awaitable&lt;&gt;</code>.
</li>
</ul></div>
</li>
<li class="listitem">
Added a new <code class="computeroutput">DynamicBuffer_v2</code> concept which is CopyConstructible.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
This change adds a new set of type requirements for dynamic buffers,
<code class="computeroutput">DynamicBuffer_v2</code>, which supports copy construction.
These new type requirements enable dynamic buffers to be used as
arguments to user-defined composed operations, where the same dynamic
buffer object is used repeatedly for multiple underlying operations.
For example:<br>
<pre class="programlisting">template &lt;typename DynamicBuffer&gt;
void echo_line(tcp::socket&amp; sock, DynamicBuffer buf)
{
n = asio::read_until(sock, buf, '\n');
asio::write(sock, buf, asio::transfer_exactly(n));
}
</pre>
<br>
</li>
<li class="listitem">
The original <code class="computeroutput">DynamicBuffer</code> type requirements have been
renamed to <code class="computeroutput">DynamicBuffer_v1</code>. These requirements continue
to be compatible with the Networking TS.
</li>
<li class="listitem">
New type traits <code class="computeroutput">is_dynamic_buffer_v1</code> and <code class="computeroutput">is_dynamic_buffer_v2</code>
have been added to test for conformance to <code class="computeroutput">DynamicBuffer_v1</code>
and <code class="computeroutput">DynamicBuffer_v2</code> respectively. The existing <code class="computeroutput">is_dynamic_buffer</code>
trait has been retained and delegates to <code class="computeroutput">is_dynamic_buffer_v1</code>
(unless <code class="computeroutput">ASIO_NO_DYNAMIC_BUFFER_V1</code> is explicitly defined,
in which case it delegates to <code class="computeroutput">is_dynamic_buffer_v2</code>).
</li>
<li class="listitem">
For convenience, the <code class="computeroutput">dynamic_string_buffer</code> and <code class="computeroutput">dynamic_vector_buffer</code>
classes conform to both <code class="computeroutput">DynamicBuffer_v1</code> and <code class="computeroutput">DynamicBuffer_v2</code>
requirements.
</li>
<li class="listitem">
When <code class="computeroutput">ASIO_NO_DYNAMIC_BUFFER_V1</code> is defined, all support
for <code class="computeroutput">DynamicBuffer_v1</code> types and functions is #ifdef-ed
out. Support for using <code class="computeroutput">basic_streambuf</code> with the <code class="computeroutput">read</code>,
<code class="computeroutput">async_read</code>, <code class="computeroutput">read_until</code>, <code class="computeroutput">async_read_until</code>,
<code class="computeroutput">write</code>, and <code class="computeroutput">async_write</code> functions is also
disabled as a consequence.
</li>
<li class="listitem">
Note: This change should have no impact on existing source code that
simply uses dynamic buffers in conjunction with Asio's composed operations.
</li>
</ul></div>
</li>
<li class="listitem">
Added a new <code class="computeroutput">async_compose</code> function that simplifies the implementation
of user-defined asynchronous operations.
</li>
<li class="listitem">
Added a <code class="computeroutput">make_strand</code> function, which creates a <code class="computeroutput">strand</code>
with a deduced <code class="computeroutput">Executor</code> template argument.
</li>
<li class="listitem">
Relaxed the completion condition type requirements to only require move-constructibility
rather than copy-constructibility.
</li>
<li class="listitem">
Added a constructor for <code class="computeroutput">local::basic_endpoint</code> that takes a
<code class="computeroutput">string_view</code>.
</li>
<li class="listitem">
Added the noexcept qualifier to various member functions of the <code class="computeroutput">ip::address</code>,
<code class="computeroutput">ip::address_v4</code>, <code class="computeroutput">ip::address_v6</code>, <code class="computeroutput">ip::basic_endpoint</code>,
and <code class="computeroutput">executor_work_guard</code> classes.
</li>
<li class="listitem">
Added the noexcept qualifier to the <code class="computeroutput">buffer_sequence_begin</code>
and <code class="computeroutput">buffer_sequence_end</code> functions.
</li>
<li class="listitem">
Added a new <code class="computeroutput">ASIO_DISABLE_VISIBILITY</code> configuration <code class="computeroutput">#define</code>
that allows visibility pragmas to be disabled. (Note: If symbols are hidden,
extra care must be taken to ensure that Asio types are not passed across
shared library API boundaries.)
</li>
<li class="listitem">
Changed compile-time feature detection to define <code class="computeroutput">ASIO_STANDALONE</code>
automatically if C++11 or later is detected.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Users should define <code class="computeroutput">ASIO_ENABLE_BOOST</code> to explicitly
disable standalone mode when compiling with C++11 or later.
</li>
<li class="listitem">
The <code class="computeroutput">configure</code> script now defaults to a standalone build
unless Boost is specified or detected.
</li>
</ul></div>
</li>
<li class="listitem">
Enabled recycling of the memory used to type-erase a function object with
the polymorphic executor.
</li>
<li class="listitem">
Changed receive operations to return the correct number of bytes transferred
when truncation (<code class="computeroutput">error::message_size</code>) occurs on a datagram-oriented
socket.
</li>
<li class="listitem">
Fixed multicast behaviour on QNX by automatically applying <code class="computeroutput">SO_REUSEPORT</code>
when the <code class="computeroutput">reuse_address</code> option is set.
</li>
<li class="listitem">
Added inclusion of <code class="computeroutput">unistd.h</code> when targeting Haiku OS, to fix
feature detection.
</li>
<li class="listitem">
Added the <code class="computeroutput">network_v[46].hpp</code> headers to the top-level convenience
header.
</li>
<li class="listitem">
Fixed calculation of absolute timeout when the backend uses <code class="computeroutput">pthread_cond_timedwait</code>.
</li>
<li class="listitem">
Changed the range-based asynchronous connect operation to deduce the <code class="computeroutput">EndpointSequence</code>
iterator type rather than assume the presence of a <code class="computeroutput">const_iterator</code>
typedef.
</li>
<li class="listitem">
Fixed <code class="computeroutput">buffer_sequence_begin</code> and <code class="computeroutput">buffer_sequence_end</code>
to prevent implicit conversion. This change addresses an issue where a
call to <code class="computeroutput">buffer_sequence_begin</code> or <code class="computeroutput">buffer_sequence_end</code>
could trigger an implicit conversion to <code class="computeroutput">const_buffer</code> or <code class="computeroutput">mutable_buffer</code>.
Whenever this implicit conversion occurred, the return value of <code class="computeroutput">buffer_sequence_begin</code>
or <code class="computeroutput">buffer_sequence_end</code> would point to a temporary object.
</li>
<li class="listitem">
Ensured SSL handshake errors are propagated to the peer before the local
operation completes.
</li>
<li class="listitem">
Suppressed the <code class="computeroutput">eof</code> error on SSL shutdown as it actually indicates
success.
</li>
<li class="listitem">
Added a fallback error code for when we OpenSSL produces an <code class="computeroutput">SSL_ERROR_SYSCALL</code>
result without an associated error.
</li>
<li class="listitem">
Changed composed asynchronous read and write operations to move, rather
than copy, the buffer sequence objects when the composed operation implementation
is moved.
</li>
<li class="listitem">
Changed to use <code class="computeroutput">&lt;atomic&gt;</code> when targeting apple/clang/libc++
with recent Xcode versions, even for C++03. This fixes a warning about
the deprecation of <code class="computeroutput">OSMemoryBarrier</code>.
</li>
<li class="listitem">
Fixed compile errors that occur when using the composed read and write
operations with MSVC 11.0, by disabling <code class="computeroutput">decltype</code> support for
that compiler.
</li>
<li class="listitem">
Increased the default value of <code class="computeroutput">_WIN32_WINNT</code> to <code class="computeroutput">0x0601</code>
(Windows 7).
</li>
<li class="listitem">
Fixed <code class="computeroutput">dispatch</code> documentation to note that it may call the
supplied function object in the current thread.
</li>
<li class="listitem">
Updated <code class="computeroutput">post</code> and <code class="computeroutput">defer</code> documentation to clarify
the the distinction between them.
</li>
</ul></div>
<h4>
<a name="asio.history.h7"></a>
<span><a name="asio.history.asio_1_12_2"></a></span><a class="link" href="history.html#asio.history.asio_1_12_2">Asio
1.12.2</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Fixed a problem with the detection of <code class="computeroutput">std::future</code> availability
with libstdc++.
</li>
<li class="listitem">
Fixed compile error in regex overload of <code class="computeroutput">read_until</code>.
</li>
<li class="listitem">
Fixed a timer heap corruption issue that can occur when moving a cancelled
timer.
</li>
<li class="listitem">
Fixed detection of <code class="computeroutput">std::experimental::string_view</code> and <code class="computeroutput">std::string_view</code>
with newer clang/libc++.
</li>
<li class="listitem">
Fixed MSVC version detection for availability of <code class="computeroutput">std::invoke_result</code>.
</li>
<li class="listitem">
Fixed the buffer sequence traits to test the new requirements, if <code class="computeroutput">decltype</code>
is available.
</li>
<li class="listitem">
Fixed an MSVC issue when building with exceptions disabled.
</li>
<li class="listitem">
Added SSL context options for TLS v1.3.
</li>
<li class="listitem">
Added a compile-time test for TLS v1 support.
</li>
<li class="listitem">
Fixed the macro used to test for TLS v1.2 support.
</li>
<li class="listitem">
Prevented global objects from being created once per thread on Windows.
</li>
<li class="listitem">
Fixed a crash when using <code class="computeroutput">size()</code>, <code class="computeroutput">max_size()</code> or
<code class="computeroutput">empty()</code> on default-constructed resolver results.
</li>
<li class="listitem">
Changed to move the return value in basic_resolver_results::begin() to
avoid copying.
</li>
<li class="listitem">
Enabled move support for the Intel Compiler.
</li>
<li class="listitem">
Fixed <code class="computeroutput">std::string_view</code> detection issue when using clang-cl.
</li>
<li class="listitem">
Fixed the handler tracking operation name for <code class="computeroutput">io_context::executor_type::dispatch</code>.
</li>
<li class="listitem">
Fixed a buffer overflow that could occur when parsing an address string
with a 64-bit scope id.
</li>
<li class="listitem">
Added examples showing how to write composed operations.
</li>
<li class="listitem">
Added C++11 versions of the Timeouts, Timers, SOCKS4 and SSL examples.
</li>
<li class="listitem">
Fixed minor issues in documentation and examples.
</li>
</ul></div>
<h4>
<a name="asio.history.h8"></a>
<span><a name="asio.history.asio_1_12_1"></a></span><a class="link" href="history.html#asio.history.asio_1_12_1">Asio
1.12.1</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added missing const qualifier to <code class="computeroutput">basic_socket_acceptor::get_option</code>.
</li>
<li class="listitem">
Worked around a parsing error that occurs with some versions of gcc.
</li>
<li class="listitem">
Fixed broken code samples in tutorial.
</li>
<li class="listitem">
Added new experimental features. (Note that "experimental" features
may be changed without notice in subsequent releases.)
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Added <code class="computeroutput">experimental::detached</code> completion token.
</li>
<li class="listitem">
Added <code class="computeroutput">experimental::redirect_error</code> completion token.
</li>
<li class="listitem">
Added <code class="computeroutput">experimental::co_spawn</code> facility for integration
with the coroutines technical specification.
</li>
</ul></div>
</li>
<li class="listitem">
Updated timeout examples to use latest features.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Used <code class="computeroutput">asio::steady_timer</code> rather than <code class="computeroutput">asio::deadline_timer</code>.
</li>
<li class="listitem">
Used <code class="computeroutput">asio::dynamic_buffer</code> rather than <code class="computeroutput">asio::streambuf</code>.
</li>
<li class="listitem">
Used timed <code class="computeroutput">asio::io_context::run_for()</code> function for
blocking clients.
</li>
<li class="listitem">
Added example showing a custom completion token for blocking with
timeouts.
</li>
</ul></div>
</li>
<li class="listitem">
Fixed unit tests to compile when <code class="computeroutput">(BOOST_)ASIO_NO_DEPRECATED</code>
is defined.
</li>
<li class="listitem">
Changed socket iostreams to use chrono by default, to fix compatibility
with the Networking TS. Define <code class="computeroutput">(BOOST_)ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM</code>
to enable the old Boost.Date_Time interface in <code class="computeroutput">basic_socket_streambuf</code>
and <code class="computeroutput">basic_socket_iostream</code>.
</li>
<li class="listitem">
Updated examples to use chrono rather than Boost.Date_Time.
</li>
<li class="listitem">
Fixed an incorrect member function detector in the <code class="computeroutput">is_dynamic_buffer</code>
trait.
</li>
<li class="listitem">
Fixed an <code class="computeroutput">async_result</code> incompatibility with deprecated <code class="computeroutput">handler_type</code>.
</li>
<li class="listitem">
Added a missing move optimisation in the SSL stream implementation.
</li>
<li class="listitem">
Fixed incorrect <code class="computeroutput">basic_resolver_results::value_type</code> typedef.
</li>
<li class="listitem">
Fixed a compile error with some OpenSSL versions when <code class="computeroutput">SSL_OP_NO_COMPRESSION</code>
is defined.
</li>
<li class="listitem">
Changed <code class="computeroutput">add_certificate_authority</code> to process multiple certificates
in a bundle.
</li>
<li class="listitem">
Eliminated deprecation warning with MSVC by using <code class="computeroutput">std::invoke_result</code>
rather than <code class="computeroutput">std::result_of</code>.
</li>
<li class="listitem">
Changed to use <code class="computeroutput">std::string_view</code> for C++17 or later, and <code class="computeroutput">std::experimental::string_view</code>
for C++14. Define the preprocessor macro <code class="computeroutput">(BOOST_)ASIO_DISABLE_STD_STRING_VIEW</code>
to force the use of std::experimental::string_view (assuming it is available)
when compiling in C++17 mode.
</li>
<li class="listitem">
Ensured <code class="computeroutput">DynamicBuffer</code> template arguments are decayed before
using in <code class="computeroutput">enable_if</code> tests.
</li>
<li class="listitem">
Changed documentation to distinguish legacy completion handlers (which
are still required to be CopyConstructible) from new MoveConstructible
handlers.
</li>
<li class="listitem">
Suppressed a discarded return value warning in the buffer debugging support.
</li>
<li class="listitem">
Fixed <code class="computeroutput">basic_yield_context</code> to work with completion signatures
containing reference parameters.
</li>
<li class="listitem">
Ensured that stackful coroutines launched using <code class="computeroutput">spawn()</code> correctly
store decayed copies of their function and handler arguments.
</li>
<li class="listitem">
Fixed some compatibility issues with Android.
</li>
<li class="listitem">
Fixed some minor portability issues in examples.
</li>
</ul></div>
<h4>
<a name="asio.history.h9"></a>
<span><a name="asio.history.asio_1_12_0"></a></span><a class="link" href="history.html#asio.history.asio_1_12_0">Asio
1.12.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Completed the interface changes to reflect the Networking TS (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/n4656.pdf" target="_top">N4656</a>).
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
See the <a class="link" href="net_ts.html" title="Networking TS compatibility">list</a> of new interfaces
and, where applicable, the corresponding old interfaces that have
been superseded.
</li>
<li class="listitem">
The service template parameters, and the corresponding classes, are
disabled by default. For example, instead of <code class="computeroutput">basic_socket&lt;Protocol,
SocketService&gt;</code> we now have simply <code class="computeroutput">basic_socket&lt;Protocol&gt;</code>.
The old interface can be enabled by defining the <code class="computeroutput">(BOOST_)ASIO_ENABLE_OLD_SERVICES</code>
macro.
</li>
</ul></div>
</li>
<li class="listitem">
Added support for customised handler tracking.
</li>
<li class="listitem">
Added reactor-related (i.e. descriptor readiness) events to handler tracking.
</li>
<li class="listitem">
Added special <a class="link" href="overview/core/concurrency_hint.html" title="Concurrency Hints">concurrency
hint</a> values that may be used to disable locking on a per <code class="computeroutput">io_context</code>
basis.
</li>
<li class="listitem">
Enabled perfect forwarding for the first <code class="computeroutput">ssl::stream&lt;&gt;</code>
constructor argument.
</li>
<li class="listitem">
Added ability to release ownership of the underlying native socket. (Requires
Windows 8.1 or later when using the I/O completion port backend.)
</li>
</ul></div>
<h4>
<a name="asio.history.h10"></a>
<span><a name="asio.history.asio_1_11_0"></a></span><a class="link" href="history.html#asio.history.asio_1_11_0">Asio
1.11.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Implemented changes to substantially reflect the Networking Library Proposal
(<a href="../www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4370.html" target="_top">N4370</a>).
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
New <code class="computeroutput">Executor</code> type requirements and classes to support
an executor framework, including the <code class="computeroutput">execution_context</code>
base class, the <code class="computeroutput">executor_work</code> class for tracking outstanding
work, and the <code class="computeroutput">executor</code> polymorphic wrapper. Free functions
<code class="computeroutput">dispatch()</code>, <code class="computeroutput">post()</code> and <code class="computeroutput">defer()</code>
have been added and are used to submit function objects to executors.
</li>
<li class="listitem">
Completion handlers now have an associated executor and associated
allocator. The free function <code class="computeroutput">wrap()</code> is used to associate
an executor with a handler or other object. The handler hooks for
allocation, invocation and continuation have been deprecated.
</li>
<li class="listitem">
A <code class="computeroutput">system_executor</code> class has been added as a default
executor.
</li>
<li class="listitem">
The <code class="computeroutput">io_service</code> class is now derived from <code class="computeroutput">execution_context</code>
and implements the executor type requirements in its nested <code class="computeroutput">executor_type</code>
class. The member functions <code class="computeroutput">dispatch()</code>, <code class="computeroutput">post()</code>,
<code class="computeroutput">defer()</code> and <code class="computeroutput">wrap()</code> have been deprecated.
The <code class="computeroutput">io_service::work</code> class has been deprecated.
</li>
<li class="listitem">
The <code class="computeroutput">io_service</code> member function <code class="computeroutput">reset()</code>
has been renamed to <code class="computeroutput">restart()</code>. The old name is retained
for backward compatibility but has been deprecated.
</li>
<li class="listitem">
The <code class="computeroutput">make_service&lt;&gt;()</code> function is now used to add
a new service to an execution context such as an <code class="computeroutput">io_service</code>.
The <code class="computeroutput">add_service()</code> function has been deprecated.
</li>
<li class="listitem">
A new <code class="computeroutput">strand&lt;&gt;</code> template has been added to allow
strand functionality to be used with generic executor types.
</li>
<li class="listitem">
I/O objects (such as sockets and timers) now provide access to their
associated <code class="computeroutput">io_service</code> via a <code class="computeroutput">context()</code> member
function. The <code class="computeroutput">get_io_service()</code> member function is deprecated.
</li>
<li class="listitem">
All asynchronous operations and executor operations now support move-only
handlers. However, the deprecated <code class="computeroutput">io_service::post()</code>,
<code class="computeroutput">io_service::dispatch()</code>, <code class="computeroutput">io_service::strand::post()</code>
and <code class="computeroutput">io_service::strand::dispatch()</code> functions still require
copyable handlers.
</li>
<li class="listitem">
Waitable timer objects are now movable.
</li>
<li class="listitem">
Waitable timers, socket iostreams and socket streambufs now provide
an <code class="computeroutput">expiry()</code> member function for obtaining the expiry
time. The accessors <code class="computeroutput">expires_at()</code> and <code class="computeroutput">expires_after()</code>
have been deprecated, though those names are retained for the mutating
members.
</li>
<li class="listitem">
The <code class="computeroutput">std::packaged_task</code> class template is now supported
as a completion handler. The initiating operation automatically returns
the future associated with the task. The <code class="computeroutput">package()</code> function
has been added as a convenient factory for packaged tasks.
</li>
<li class="listitem">
Sockets, socket acceptors and descriptors now provide <code class="computeroutput">wait()</code>
and <code class="computeroutput">async_wait()</code> operations that may be used to wait
for readiness. The <code class="computeroutput">null_buffers</code> type has been deprecated.
</li>
<li class="listitem">
The proposed error code enum classes are simulated using namespaces.
Existing asio error codes now have a correspondence with the standard
error conditions.
</li>
<li class="listitem">
Conversion between IP address types, and conversion from string to
address, is now supported via the <code class="computeroutput">address_cast&lt;&gt;()</code>,
<code class="computeroutput">make_address()</code>, <code class="computeroutput">make_address_v4()</code> and
<code class="computeroutput">make_address_v6()</code> free functions. The <code class="computeroutput">from_string()</code>,
<code class="computeroutput">to_v4()</code>, <code class="computeroutput">to_v6()</code> and <code class="computeroutput">v4_mapped()</code>
member functions have been deprecated.
</li>
<li class="listitem">
A default-constructed <code class="computeroutput">ip::address</code> now represents an
invalid address value that is neither IPv4 nor IPv6.
</li>
<li class="listitem">
New <code class="computeroutput">buffer()</code> overloads that generate mutable buffers
for non-const <code class="computeroutput">string</code> objects.
</li>
<li class="listitem">
Support for dynamic buffer sequences that automatically grow and
shrink to accomodate data as it is read or written. This is a generic
facility similar to the existing <code class="computeroutput">asio::streambuf</code> class.
This support includes:
<div class="itemizedlist"><ul class="itemizedlist" type="square">
<li class="listitem">
New <code class="computeroutput">dynamic_string_buffer</code> and <code class="computeroutput">dynamic_vector_buffer</code>
adapter classes that meet the <code class="computeroutput">DynamicBufferSequence</code>
type requirements.
</li>
<li class="listitem">
New <code class="computeroutput">dynamic_buffer()</code> factory functions for creating
a dynamic buffer adapter for a <code class="computeroutput">vector</code> or <code class="computeroutput">string</code>.
</li>
<li class="listitem">
New overloads for the <code class="computeroutput">read()</code>, <code class="computeroutput">async_read()</code>,
<code class="computeroutput">write()</code> and <code class="computeroutput">async_write()</code>, <code class="computeroutput">read_until()</code>
and <code class="computeroutput">async_read_until()</code> free functions that directly
support dynamic buffer sequences.
</li>
</ul></div>
</li>
<li class="listitem">
Support for networks and address ranges. Thanks go to Oliver Kowalke
for contributing to the design and providing the implementation on
which this facility is based. The following new classes have been
added:
<div class="itemizedlist"><ul class="itemizedlist" type="square">
<li class="listitem">
<code class="computeroutput">address_iterator_v4</code> for iterating across IPv4
addresses
</li>
<li class="listitem">
<code class="computeroutput">address_iterator_v6</code> for iterating across IPv6
addresses
</li>
<li class="listitem">
<code class="computeroutput">address_range_v4</code> to represent a range of IPv4
addresses
</li>
<li class="listitem">
<code class="computeroutput">address_range_v6</code> to represent a range of IPv6
addresses
</li>
<li class="listitem">
<code class="computeroutput">network_v4</code> for manipulating IPv4 CIDR addresses,
e.g. 1.2.3.0/24
</li>
<li class="listitem">
<code class="computeroutput">network_v6</code> for manipulating IPv6 CIDR addresses,
e.g. ffe0:/120
</li>
</ul></div>
</li>
<li class="listitem">
New convenience headers in <code class="literal">&lt;asio/ts/*.hpp&gt;</code>
that correspond to the headers in the proposal.
</li>
</ul></div>
</li>
<li class="listitem">
Added a new, executor-aware <code class="computeroutput">thread_pool</code> class.
</li>
<li class="listitem">
Changed <code class="computeroutput">spawn()</code> to be executor-aware.
</li>
<li class="listitem">
Added a new <code class="computeroutput">spawn()</code> overload that takes only a function object.
</li>
<li class="listitem">
Changed <code class="computeroutput">spawn()</code> and <code class="computeroutput">yield_context</code> to permit nested
calls to the completion handler.
</li>
<li class="listitem">
Removed previously deprecated functions.
</li>
<li class="listitem">
Added options for disabling TLS v1.1 and v1.2.
</li>
<li class="listitem">
Changed the SSL wrapper to call the password callback when loading an in-memory
key.
</li>
<li class="listitem">
Changed the tutorial to use <code class="computeroutput">std::endl</code> to ensure output is
flushed.
</li>
<li class="listitem">
Fixed false SSL error reports by ensuring that the SSL error queue is cleared
prior to each operation.
</li>
<li class="listitem">
Fixed an <code class="computeroutput">ssl::stream&lt;&gt;</code> bug that may result in spurious
'short read' errors.
</li>
<li class="listitem">
Enabled perfect forwarding for the first <code class="computeroutput">ssl::stream&lt;&gt;</code>
constructor argument.
</li>
<li class="listitem">
Added standalone Asio support for Clang when used with libstdc++ and C++11.
</li>
<li class="listitem">
Fixed an unsigned integer overflow reported by Clang's integer sanitizer.
</li>
<li class="listitem">
Added support for move-only return types when using a <code class="computeroutput">yield_context</code>
object with asynchronous operations.
</li>
<li class="listitem">
Ensured errors generated by Windows' <code class="computeroutput">ConnectEx</code> function are
mapped to their portable equivalents.
</li>
<li class="listitem">
Changed multicast test to treat certain <code class="computeroutput">join_group</code> failures
as non-fatal.
</li>
</ul></div>
<h4>
<a name="asio.history.h11"></a>
<span><a name="asio.history.asio_1_10_5"></a></span><a class="link" href="history.html#asio.history.asio_1_10_5">Asio
1.10.5</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Fixed the <code class="literal">kqueue</code> reactor so that it works on FreeBSD.
</li>
<li class="listitem">
Fixed an issue in the <code class="literal">kqueue</code> reactor which resulted
in spinning when using serial ports on Mac OS.
</li>
<li class="listitem">
Fixed <code class="literal">kqueue</code> reactor support for read-only file descriptors.
</li>
<li class="listitem">
Fixed a compile error when using the <code class="literal">/dev/poll</code> reactor.
</li>
<li class="listitem">
Changed the Windows backend to use <code class="computeroutput">WSASocketW</code>, as <code class="computeroutput">WSASocketA</code>
has been deprecated.
</li>
<li class="listitem">
Fixed some warnings reported by Visual C++ 2013.
</li>
<li class="listitem">
Fixed integer type used in the WinRT version of the byte-order conversion
functions.
</li>
<li class="listitem">
Changed documentation to indicate that <code class="computeroutput">use_future</code> and <code class="computeroutput">spawn()</code>
are not made available when including the <code class="computeroutput">asio.hpp</code> convenience
header.
</li>
<li class="listitem">
Explicitly marked <code class="computeroutput">asio::strand</code> as deprecated. Use <code class="computeroutput">asio::io_service::strand</code>
instead.
</li>
</ul></div>
<h4>
<a name="asio.history.h12"></a>
<span><a name="asio.history.asio_1_10_4"></a></span><a class="link" href="history.html#asio.history.asio_1_10_4">Asio
1.10.4</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Stopped using certain Winsock functions that are marked as deprecated in
the latest Visual C++ and Windows SDK.
</li>
<li class="listitem">
Fixed a shadow variable warning on Windows.
</li>
<li class="listitem">
Fixed a regression in the <code class="literal">kqueue</code> backend that was introduced
in Asio 1.10.2.
</li>
<li class="listitem">
Added a workaround for building the unit tests with <code class="literal">gcc</code>
on AIX.
</li>
</ul></div>
<h4>
<a name="asio.history.h13"></a>
<span><a name="asio.history.asio_1_10_3"></a></span><a class="link" href="history.html#asio.history.asio_1_10_3">Asio
1.10.3</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Worked around a <code class="literal">gcc</code> problem to do with anonymous enums.
</li>
<li class="listitem">
Reverted the Windows <code class="computeroutput">HANDLE</code> backend change to ignore <code class="computeroutput">ERROR_MORE_DATA</code>.
Instead, the error will be propagated as with any other (i.e. in an <code class="computeroutput">error_code</code>
or thrown as a <code class="computeroutput">system_error</code>), and the number of bytes transferred
will be returned. For code that needs to handle partial messages, the
<code class="computeroutput">error_code</code> overload should be used.
</li>
<li class="listitem">
Fixed an off-by-one error in the <code class="computeroutput">signal_set</code> implementation's
signal number check.
</li>
<li class="listitem">
Changed the Windows IOCP backend to not assume that <code class="computeroutput">SO_UPDATE_CONNECT_CONTEXT</code>
is defined.
</li>
<li class="listitem">
Fixed a Windows-specific issue, introduced in Asio 1.10.2, by using <code class="computeroutput">VerifyVersionInfo</code>
rather than <code class="computeroutput">GetVersionEx</code>, as <code class="computeroutput">GetVersionEx</code> has
been deprecated.
</li>
<li class="listitem">
Changed to use SSE2 intrinsics rather than inline assembly, to allow the
Cray compiler to work.
</li>
</ul></div>
<h4>
<a name="asio.history.h14"></a>
<span><a name="asio.history.asio_1_10_2"></a></span><a class="link" href="history.html#asio.history.asio_1_10_2">Asio
1.10.2</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Fixed <code class="computeroutput">asio::spawn()</code> to work correctly with new Boost.Coroutine
interface.
</li>
<li class="listitem">
Ensured that incomplete <code class="computeroutput">asio::spawn()</code> coroutines are correctly
unwound when cleaned up by the <code class="computeroutput">io_service</code> destructor.
</li>
<li class="listitem">
Fixed delegation of continuation hook for handlers produced by <code class="computeroutput">io_service::wrap()</code>
and <code class="computeroutput">strand::wrap()</code>.
</li>
<li class="listitem">
Changed the Windows I/O completion port backend to use <code class="computeroutput">ConnectEx</code>,
if available, for connection-oriented IP sockets.
</li>
<li class="listitem">
Changed the <code class="computeroutput">io_service</code> backend for non-Windows (and non-IOCP
Windows) platforms to use a single condition variable per <code class="computeroutput">io_service</code>
instance. This addresses a potential race condition when <code class="computeroutput">run_one()</code>
is used from multiple threads.
</li>
<li class="listitem">
Prevented integer overflow when computing timeouts based on some <code class="computeroutput">boost::chrono</code>
and <code class="computeroutput">std::chrono</code> clocks.
</li>
<li class="listitem">
Made further changes to <code class="computeroutput">EV_CLEAR</code> handling in the kqueue backend,
to address other cases where the <code class="computeroutput">close()</code> system call may hang
on Mac OS X.
</li>
<li class="listitem">
Fixed infinite recursion in implementation of <code class="computeroutput">resolver_query_base::flags::operator~</code>.
</li>
<li class="listitem">
Made the <code class="computeroutput">select</code> reactor more efficient on Windows for large
numbers of sockets.
</li>
<li class="listitem">
Fixed a Windows-specific type-aliasing issue reported by <code class="literal">gcc</code>.
</li>
<li class="listitem">
Prevented execution of compile-time-only buffer test to avoid triggering
an address sanitiser warning.
</li>
<li class="listitem">
Disabled the <code class="computeroutput">GetQueuedCompletionStatus</code> timeout workaround
on recent versions of Windows.
</li>
<li class="listitem">
Changed implementation for Windows Runtime to use <code class="computeroutput">FormatMessageW</code>
rather than <code class="computeroutput">FormatMessageA</code>, as the Windows store does not
permit the latter.
</li>
<li class="listitem">
Added support for string-based scope IDs when using link-local multicast
addresses.
</li>
<li class="listitem">
Changed IPv6 multicast group join to use the address's scope ID as the
interface, if an interface is not explicitly specified.
</li>
<li class="listitem">
Fixed multicast test failure on Mac OS X and the BSDs by using a link-local
multicast address.
</li>
<li class="listitem">
Various minor documentation improvements.
</li>
</ul></div>
<h4>
<a name="asio.history.h15"></a>
<span><a name="asio.history.asio_1_10_1"></a></span><a class="link" href="history.html#asio.history.asio_1_10_1">Asio
1.10.1</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Implemented a limited port to Windows Runtime. This support requires that
the language extensions be enabled. Due to the restricted facilities exposed
by the Windows Runtime API, the port also comes with the following caveats:
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
The core facilities such as the <code class="computeroutput">io_service</code>, <code class="computeroutput">strand</code>,
buffers, composed operations, timers, etc., should all work as normal.
</li>
<li class="listitem">
For sockets, only client-side TCP is supported.
</li>
<li class="listitem">
Explicit binding of a client-side TCP socket is not supported.
</li>
<li class="listitem">
The <code class="computeroutput">cancel()</code> function is not supported for sockets.
Asynchronous operations may only be cancelled by closing the socket.
</li>
<li class="listitem">
Operations that use <code class="computeroutput">null_buffers</code> are not supported.
</li>
<li class="listitem">
Only <code class="computeroutput">tcp::no_delay</code> and <code class="computeroutput">socket_base::keep_alive</code>
options are supported.
</li>
<li class="listitem">
Resolvers do not support service names, only numbers. I.e. you must
use "80" rather than "http".
</li>
<li class="listitem">
Most resolver query flags have no effect.
</li>
</ul></div>
</li>
<li class="listitem">
Extended the ability to use Asio without Boost to include Microsoft Visual
Studio 2012. When using a C++11 compiler, most of Asio may now be used
without a dependency on Boost header files or libraries. To use Asio in
this way, define <code class="computeroutput">ASIO_STANDALONE</code> on your compiler command
line or as part of the project options. This standalone configuration has
been tested for the following platforms and compilers:
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Microsoft Visual Studio 2012
</li>
<li class="listitem">
Linux with g++ 4.7 or 4.8 (requires <code class="literal">-std=c++11</code>)
</li>
<li class="listitem">
Mac OS X with clang++ / Xcode 4.6 (requires <code class="literal">-std=c++11 -stdlib=libc++</code>)
</li>
</ul></div>
</li>
<li class="listitem">
Fixed a regression (introduced in 1.10.0) where, on some platforms, errors
from <code class="computeroutput">async_connect</code> were not correctly propagated through to
the completion handler.
</li>
<li class="listitem">
Fixed a Windows-specific regression (introduced in 1.10.0) that occurs
when multiple threads are running an <code class="computeroutput">io_service</code>. When the
bug occurs, the result of an asynchronous operation (error and bytes tranferred)
is incorrectly discarded and zero values used instead. For TCP sockets
this results in spurious end-of-file notifications.
</li>
<li class="listitem">
Fixed a bug in handler tracking, where it was not correctly printing out
some handler IDs.
</li>
<li class="listitem">
Fixed the comparison used to test for successful synchronous accept operations
so that it works correctly with unsigned socket descriptors.
</li>
<li class="listitem">
Ensured the signal number is correctly passed to the completion handler
when starting an <code class="computeroutput">async_wait</code> on a signal that is already raised.
</li>
<li class="listitem">
Suppressed a g++ 4.8+ warning about unused typedefs.
</li>
<li class="listitem">
Enabled the move optimisation for handlers that use the default invocation
hook.
</li>
<li class="listitem">
Clarified that programs must not issue overlapping <code class="computeroutput">async_write_at</code>
operations.
</li>
<li class="listitem">
Changed the Windows <code class="computeroutput">HANDLE</code> backend to treat <code class="computeroutput">ERROR_MORE_DATA</code>
as a non-fatal error when returned by <code class="computeroutput">GetOverlappedResult</code>
for a synchronous read.
</li>
<li class="listitem">
Visual C++ language extensions use <code class="computeroutput">generic</code> as a keyword. Added
a workaround that renames the namespace to <code class="computeroutput">cpp_generic</code> when
those language extensions are in effect.
</li>
<li class="listitem">
Fixed some asynchronous operations that missed out on getting <code class="computeroutput">async_result</code>
support in 1.10.0. In particular, the buffered stream templates have been
updated so that they adhere to current handler patterns.
</li>
<li class="listitem">
Enabled move support for Microsoft Visual Studio 2012.
</li>
<li class="listitem">
Added <code class="computeroutput">use_future</code> support for Microsoft Visual Studio 2012.
</li>
<li class="listitem">
Removed a use of <code class="computeroutput">std::min</code> in the Windows IOCP backend to avoid
a dependency on the <code class="computeroutput">&lt;algorithm&gt;</code> header.
</li>
<li class="listitem">
Eliminated some unnecessary handler copies.
</li>
<li class="listitem">
Fixed support for older versions of OpenSSL that do not provide the <code class="computeroutput">SSL_CTX_clear_options</code>
function.
</li>
<li class="listitem">
Fixed various minor and cosmetic issues in code and documentation.
</li>
</ul></div>
<h4>
<a name="asio.history.h16"></a>
<span><a name="asio.history.asio_1_10_0"></a></span><a class="link" href="history.html#asio.history.asio_1_10_0">Asio
1.10.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added new traits classes, <code class="computeroutput">handler_type</code> and <code class="computeroutput">async_result</code>,
that allow the customisation of the return type of an initiating function.
</li>
<li class="listitem">
Added the <code class="computeroutput">asio::spawn()</code> function, a high-level wrapper for
running stackful coroutines, based on the Boost.Coroutine library. The
<code class="computeroutput">spawn()</code> function enables programs to implement asynchronous
logic in a synchronous manner. For example: <code class="computeroutput">size_t n = my_socket.async_read_some(my_buffer,
yield);</code>. For further information, see <a class="link" href="overview/core/spawn.html" title="Stackful Coroutines">Stackful
Coroutines</a>.
</li>
<li class="listitem">
Added the <code class="computeroutput">asio::use_future</code> special value, which provides first-class
support for returning a C++11 <code class="computeroutput">std::future</code> from an asynchronous
operation's initiating function. For example: <code class="computeroutput">future&lt;size_t&gt;
= my_socket.async_read_some(my_buffer, asio::use_future);</code>. For further
information, see <a class="link" href="overview/cpp2011/futures.html" title="Futures">C++ 2011
Support - Futures</a>.
</li>
<li class="listitem">
Promoted the stackless coroutine class and macros to be part of Asio's
documented interface, rather than part of the HTTP server 4 example. For
further information, see <a class="link" href="overview/core/coroutine.html" title="Stackless Coroutines">Stackless
Coroutines</a>.
</li>
<li class="listitem">
Added a new handler hook called <code class="computeroutput">asio_handler_is_continuation</code>.
Asynchronous operations may represent a continuation of the asynchronous
control flow associated with the current executing handler. The <code class="computeroutput">asio_handler_is_continuation</code>
hook can be customised to return <code class="computeroutput">true</code> if this is the case,
and Asio's implementation can use this knowledge to optimise scheduling
of the new handler. To cover common cases, Asio customises the hook for
strands, <code class="computeroutput">spawn()</code> and composed asynchronous operations.
</li>
<li class="listitem">
Added four new generic protocol classes, <code class="computeroutput">generic::datagram_protocol</code>,
<code class="computeroutput">generic::raw_protocol</code>, <code class="computeroutput">generic::seq_packet_protocol</code>
and <code class="computeroutput">generic::stream_protocol</code>, which implement the <code class="computeroutput">Protocol</code>
type requirements, but allow the user to specify the address family (e.g.
<code class="computeroutput">AF_INET</code>) and protocol type (e.g. <code class="computeroutput">IPPROTO_TCP</code>)
at runtime. For further information, see <a class="link" href="overview/networking/other_protocols.html" title="Support for Other Protocols">Support
for Other Protocols</a>.
</li>
<li class="listitem">
Added C++11 move constructors that allow the conversion of a socket (or
acceptor) into a more generic type. For example, an <code class="computeroutput">ip::tcp::socket</code>
can be converted into a <code class="computeroutput">generic::stream_protocol::socket</code> via
move construction. For further information, see <a class="link" href="overview/networking/other_protocols.html" title="Support for Other Protocols">Support
for Other Protocols</a>.
</li>
<li class="listitem">
Extended the <code class="computeroutput">basic_socket_acceptor&lt;&gt;</code>'s <code class="computeroutput">accept()</code>
and <code class="computeroutput">async_accept()</code> functions to allow a new connection to
be accepted directly into a socket of a more generic type. For example,
an <code class="computeroutput">ip::tcp::acceptor</code> can be used to accept into a <code class="computeroutput">generic::stream_protocol::socket</code>
object. For further information, see <a class="link" href="overview/networking/other_protocols.html" title="Support for Other Protocols">Support
for Other Protocols</a>.
</li>
<li class="listitem">
Moved existing examples into a C++03-specific directory, and added a new
directory for C++11-specific examples. A limited subset of the C++03 examples
have been converted to their C++11 equivalents.
</li>
<li class="listitem">
Add the ability to use Asio without Boost, for a limited set of platforms.
When using a C++11 compiler, most of Asio may now be used without a dependency
on Boost header files or libraries. To use Asio in this way, define <code class="computeroutput">ASIO_STANDALONE</code>
on your compiler command line or as part of the project options. This standalone
configuration has currently been tested for the following platforms and
compilers:
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Linux with g++ 4.7 (requires <code class="literal">-std=c++11</code>)
</li>
<li class="listitem">
Mac OS X with clang++ / Xcode 4.6 (requires <code class="literal">-std=c++11 -stdlib=libc++</code>)
</li>
</ul></div>
</li>
<li class="listitem">
Various SSL enhancements. Thanks go to Nick Jones, on whose work these
changes are based.
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Added support for SSL handshakes with re-use of data already read
from the wire. New overloads of the <code class="computeroutput">ssl::stream&lt;&gt;</code>
class's <code class="computeroutput">handshake()</code> and <code class="computeroutput">async_handshake()</code>
functions have been added. These accept a <code class="computeroutput">ConstBufferSequence</code>
to be used as initial input to the ssl engine for the handshake procedure.
</li>
<li class="listitem">
Added support for creation of TLSv1.1 and TLSv1.2 <code class="computeroutput">ssl::context</code>
objects.
</li>
<li class="listitem">
Added a <code class="computeroutput">set_verify_depth()</code> function to the <code class="computeroutput">ssl::context</code>
and <code class="computeroutput">ssl::stream&lt;&gt;</code> classes.
</li>
<li class="listitem">
Added the ability to load SSL certificate and key data from memory
buffers. New functions, <code class="computeroutput">add_certificate_authority()</code>,
<code class="computeroutput">use_certificate()</code>, <code class="computeroutput">use_certificate_chain()</code>,
<code class="computeroutput">use_private_key()</code>, <code class="computeroutput">use_rsa_private_key()</code>
and <code class="computeroutput">use_tmp_dh()</code>, have been added to the <code class="computeroutput">ssl::context</code>
class.
</li>
<li class="listitem">
Changed <code class="computeroutput">ssl::context</code> to automatically disable SSL compression
by default. To enable, use the new <code class="computeroutput">ssl::context::clear_options()</code>
function, as in <code class="computeroutput">my_context.clear_options(ssl::context::no_compression)</code>.
</li>
</ul></div>
</li>
<li class="listitem">
Fixed a potential deadlock in <code class="computeroutput">signal_set</code> implementation.
</li>
<li class="listitem">
Fixed an error in acceptor example in documentation.
</li>
<li class="listitem">
Fixed copy-paste errors in waitable timer documentation.
</li>
<li class="listitem">
Added assertions to satisfy some code analysis tools.
</li>
<li class="listitem">
Fixed a malformed <code class="computeroutput">#warning</code> directive.
</li>
<li class="listitem">
Fixed a potential data race in the Linux <code class="computeroutput">epoll</code> implementation.
</li>
<li class="listitem">
Fixed a Windows-specific bug, where certain operations might generate an
<code class="computeroutput">error_code</code> with an invalid (i.e. <code class="computeroutput">NULL</code>) <code class="computeroutput">error_category</code>.
</li>
<li class="listitem">
Fixed <code class="computeroutput">basic_waitable_timer</code>'s underlying implementation so
that it can handle any <code class="computeroutput">time_point</code> value without overflowing
the intermediate duration objects.
</li>
<li class="listitem">
Fixed a problem with lost thread wakeups that can occur when making concurrent
calls to <code class="computeroutput">run()</code> and <code class="computeroutput">poll()</code> on the same <code class="computeroutput">io_service</code>
object.
</li>
<li class="listitem">
Fixed implementation of asynchronous connect operation so that it can cope
with spurious readiness notifications from the reactor.
</li>
<li class="listitem">
Fixed a memory leak in the <code class="computeroutput">ssl::rfc2818_verification</code> class.
</li>
<li class="listitem">
Added a mechanism for disabling automatic Winsock initialisation. See the
header file <code class="literal">asio/detail/winsock_init.hpp</code> for details.
</li>
</ul></div>
<h4>
<a name="asio.history.h17"></a>
<span><a name="asio.history.asio_1_8_3"></a></span><a class="link" href="history.html#asio.history.asio_1_8_3">Asio
1.8.3</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Fixed some 64-to-32-bit conversion warnings.
</li>
<li class="listitem">
Fixed various small errors in documentation and comments.
</li>
<li class="listitem">
Fixed an error in the example embedded in <code class="computeroutput">basic_socket::get_option</code>'s
documentation.
</li>
<li class="listitem">
Changed to use <code class="computeroutput">long</code> rather than <code class="computeroutput">int</code> for SSL_CTX
options, to match OpenSSL.
</li>
<li class="listitem">
Changed to use <code class="computeroutput">_snwprintf</code> to address a compile error due to
the changed <code class="computeroutput">swprintf</code> signature in recent versions of MinGW.
</li>
<li class="listitem">
Fixed a deadlock that can occur on Windows when shutting down a pool of
<code class="computeroutput">io_service</code> threads due to running out of work.
</li>
<li class="listitem">
Changed UNIX domain socket example to treat errors from <code class="computeroutput">accept</code>
as non-fatal.
</li>
<li class="listitem">
Added a small block recycling optimisation to improve default memory allocation
behaviour.
</li>
</ul></div>
<h4>
<a name="asio.history.h18"></a>
<span><a name="asio.history.asio_1_8_2"></a></span><a class="link" href="history.html#asio.history.asio_1_8_2">Asio
1.8.2</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Fixed an incompatibility between <code class="computeroutput">ip::tcp::iostream</code> and C++11.
</li>
<li class="listitem">
Decorated GCC attribute names with underscores to prevent interaction with
user-defined macros.
</li>
<li class="listitem">
Added missing <code class="computeroutput">#include &lt;cctype&gt;</code>, needed for some versions
of MinGW.
</li>
<li class="listitem">
Changed to use <code class="literal">gcc</code>'s atomic builtins on ARM CPUs, when
available.
</li>
<li class="listitem">
Changed strand destruction to be a no-op, to allow strand objects to be
destroyed after their associated <code class="computeroutput">io_service</code> has been destroyed.
</li>
<li class="listitem">
Added support for some newer versions of glibc which provide the <code class="computeroutput">epoll_create1()</code>
function but always fail with ENOSYS.
</li>
<li class="listitem">
Changed the SSL implementation to throw an exception if SSL engine initialisation
fails.
</li>
<li class="listitem">
Fixed another regression in <code class="computeroutput">buffered_write_stream</code>.
</li>
<li class="listitem">
Implemented various minor performance improvements, primarily targeted
at Linux x86 and x86-64 platforms.
</li>
</ul></div>
<h4>
<a name="asio.history.h19"></a>
<span><a name="asio.history.asio_1_8_1"></a></span><a class="link" href="history.html#asio.history.asio_1_8_1">Asio
1.8.1</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Changed the <code class="computeroutput">epoll_reactor</code> backend to do lazy registration
for <code class="computeroutput">EPOLLOUT</code> events.
</li>
<li class="listitem">
Fixed the <code class="computeroutput">epoll_reactor</code> handling of out-of-band data, which
was broken by an incomplete fix in the last release.
</li>
<li class="listitem">
Changed Asio's SSL wrapper to respect OpenSSL's <code class="computeroutput">OPENSSL_NO_ENGINE</code>
feature test <code class="computeroutput">#define</code>.
</li>
<li class="listitem">
Fixed <code class="computeroutput">windows::object_handle</code> so that it works with Windows
compilers that support C++11 move semantics (such as <code class="literal">g++</code>).
</li>
<li class="listitem">
Improved the performance of strand rescheduling.
</li>
<li class="listitem">
Added support for <code class="literal">g++</code> 4.7 when compiling in C++11 mode.
</li>
<li class="listitem">
Fixed a problem where <code class="computeroutput">signal_set</code> handlers were not being delivered
when the <code class="computeroutput">io_service</code> was constructed with a <code class="computeroutput">concurrency_hint</code>
of 1.
</li>
</ul></div>
<h4>
<a name="asio.history.h20"></a>
<span><a name="asio.history.asio_1_8_0"></a></span><a class="link" href="history.html#asio.history.asio_1_8_0">Asio
1.8.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added a new class template <code class="computeroutput">basic_waitable_timer</code> based around
the C++11 clock type requirements. It may be used with the clocks from
the C++11 <code class="computeroutput">&lt;chrono&gt;</code> library facility or, if those are
not available, Boost.Chrono. The typedefs <code class="computeroutput">high_resolution_timer</code>,
<code class="computeroutput">steady_timer</code> and <code class="computeroutput">system_timer</code> may be used to
create timer objects for the standard clock types.
</li>
<li class="listitem">
Added a new <code class="computeroutput">windows::object_handle</code> class for performing waits
on Windows kernel objects. Thanks go to Boris Schaeling for contributing
substantially to the development of this feature.
</li>
<li class="listitem">
On Linux, <code class="computeroutput">connect()</code> can return EAGAIN in certain circumstances.
Remapped this to another error so that it doesn't look like a non-blocking
operation.
</li>
<li class="listitem">
Fixed a compile error on NetBSD.
</li>
<li class="listitem">
Fixed deadlock on Mac OS X.
</li>
<li class="listitem">
Fixed a regression in <code class="computeroutput">buffered_write_stream</code>.
</li>
<li class="listitem">
Fixed a non-paged pool "leak" on Windows when an <code class="computeroutput">io_service</code>
is repeatedly run without anything to do.
</li>
<li class="listitem">
Reverted earlier change to allow some speculative operations to be performed
without holding the lock, as it introduced a race condition in some multithreaded
scenarios.
</li>
<li class="listitem">
Fixed a bug where the second buffer in an array of two buffers may be ignored
if the first buffer is empty.
</li>
</ul></div>
<h4>
<a name="asio.history.h21"></a>
<span><a name="asio.history.asio_1_6_1"></a></span><a class="link" href="history.html#asio.history.asio_1_6_1">Asio
1.6.1</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Implemented various performance improvements, including:
<div class="itemizedlist"><ul class="itemizedlist" type="circle">
<li class="listitem">
Using thread-local operation queues in single-threaded use cases
(i.e. when <code class="computeroutput">concurrency_hint</code> is 1) to eliminate a lock/unlock
pair.
</li>
<li class="listitem">
Allowing some <code class="computeroutput">epoll_reactor</code> speculative operations to
be performed without holding the lock.
</li>
<li class="listitem">
Improving locality of reference by performing an <code class="computeroutput">epoll_reactor</code>'s
I/O operation immediately before the corresponding handler is called.
This also improves scalability across CPUs when multiple threads
are running the <code class="computeroutput">io_service</code>.
</li>
<li class="listitem">
Specialising asynchronous read and write operations for buffer sequences
that are arrays (<code class="computeroutput">boost::array</code> or <code class="computeroutput">std::array</code>)
of exactly two buffers.
</li>
</ul></div>
</li>
<li class="listitem">
Fixed a compile error in the regex overload of <code class="computeroutput">async_read_until</code>.
</li>
<li class="listitem">
Fixed a Windows-specific compile error by explicitly specifying the <code class="computeroutput">signal()</code>
function from the global namespace.
</li>
<li class="listitem">
Changed the <code class="computeroutput">deadline_timer</code> implementation so that it does
not read the clock unless the timer heap is non-empty.
</li>
<li class="listitem">
Changed the SSL stream's buffers' sizes so that they are large enough to
hold a complete TLS record.
</li>
<li class="listitem">
Fixed the behaviour of the synchronous <code class="computeroutput">null_buffers</code> operations
so that they obey the user's non-blocking setting.
</li>
<li class="listitem">
Changed to set the size of the select <code class="computeroutput">fd_set</code> at runtime when
using Windows.
</li>
<li class="listitem">
Disabled an MSVC warning due to const qualifier being applied to function
type.
</li>
<li class="listitem">
Fixed a crash that occurs when using the Intel C++ compiler.
</li>
<li class="listitem">
Changed the initialisation of the OpenSSL library so that it supports all
available algorithms.
</li>
<li class="listitem">
Fixed the SSL error mapping used when the session is gracefully shut down.
</li>
<li class="listitem">
Added some latency test programs.
</li>
<li class="listitem">
Clarified that a read operation ends when the buffer is full.
</li>
<li class="listitem">
Fixed an exception safety issue in <code class="computeroutput">epoll_reactor</code> initialisation.
</li>
<li class="listitem">
Made the number of strand implementations configurable by defining <code class="computeroutput">(BOOST_)ASIO_STRAND_IMPLEMENTATIONS</code>
to the desired number.
</li>
<li class="listitem">
Added support for a new <code class="computeroutput">(BOOST_)ASIO_ENABLE_SEQUENTIAL_STRAND_ALLOCATION</code>
flag which switches the allocation of strand implementations to use a round-robin
approach rather than hashing.
</li>
<li class="listitem">
Fixed potential strand starvation issue that can occur when <code class="computeroutput">strand.post()</code>
is used.
</li>
</ul></div>
<h4>
<a name="asio.history.h22"></a>
<span><a name="asio.history.asio_1_6_0"></a></span><a class="link" href="history.html#asio.history.asio_1_6_0">Asio
1.6.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Improved support for C++0x move construction to further reduce copying
of handler objects. In certain designs it is possible to eliminate virtually
all copies. Move support is now enabled when compiling in <code class="literal">-std=c++0x</code>
mode on g++ 4.5 or higher.
</li>
<li class="listitem">
Added build support for platforms that don't provide either of <code class="computeroutput">signal()</code>
or <code class="computeroutput">sigaction()</code>.
</li>
<li class="listitem">
Changed to use C++0x variadic templates when they are available, rather
than generating function overloads using the Boost.Preprocessor library.
</li>
<li class="listitem">
Ensured the value of <code class="computeroutput">errno</code> is preserved across the implementation's
signal handler.
</li>
<li class="listitem">
On Windows, ensured the count of outstanding work is decremented for abandoned
operations (i.e. operations that are being cleaned up within the <code class="computeroutput">io_service</code>
destructor).
</li>
<li class="listitem">
Fixed behaviour of zero-length reads and writes in the new SSL implementation.
</li>
<li class="listitem">
Added support for building with OpenSSL 1.0 when <code class="computeroutput">OPENSSL_NO_SSL2</code>
is defined.
</li>
<li class="listitem">
Changed most examples to treat a failure by an accept operation as non-fatal.
</li>
<li class="listitem">
Fixed an error in the <code class="literal">tick_count_timer</code> example by making
the duration type signed. Previously, a wait on an already-passed deadline
would not return for a very long time.
</li>
</ul></div>
<h4>
<a name="asio.history.h23"></a>
<span><a name="asio.history.asio_1_5_3"></a></span><a class="link" href="history.html#asio.history.asio_1_5_3">Asio
1.5.3</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added a new, completely rewritten SSL implementation. The new implementation
compiles faster, shows substantially improved performance, and supports
custom memory allocation and handler invocation. It includes new API features
such as certificate verification callbacks and has improved error reporting.
The new implementation is source-compatible with the old for most uses.
However, if necessary, the old implementation may still be used by defining
<code class="computeroutput">(BOOST_)ASIO_ENABLE_OLD_SSL</code>.
</li>
<li class="listitem">
Added new <code class="computeroutput">asio::buffer()</code> overloads for <code class="computeroutput">std::array</code>,
when available. The support is automatically enabled when compiling in
<code class="literal">-std=c++0x</code> mode on g++ 4.3 or higher, or when using
MSVC 10. The support may be explicitly enabled by defining <code class="computeroutput">(BOOST_)ASIO_HAS_STD_ARRAY</code>,
or disabled by defining <code class="computeroutput">(BOOST_)ASIO_DISABLE_STD_ARRAY</code>.
</li>
<li class="listitem">
Changed to use the C++0x standard library templates <code class="computeroutput">array</code>,
<code class="computeroutput">shared_ptr</code>, <code class="computeroutput">weak_ptr</code> and <code class="computeroutput">atomic</code>
when they are available, rather than the Boost equivalents.
</li>
<li class="listitem">
Support for <code class="computeroutput">std::error_code</code> and <code class="computeroutput">std::system_error</code>
is no longer enabled by default for g++ 4.5, as that compiler's standard
library does not implement <code class="computeroutput">std::system_error::what()</code> correctly.
</li>
</ul></div>
<h4>
<a name="asio.history.h24"></a>
<span><a name="asio.history.asio_1_5_2"></a></span><a class="link" href="history.html#asio.history.asio_1_5_2">Asio
1.5.2</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added support for C++0x move construction and assignment to sockets, serial
ports, POSIX descriptors and Windows handles.
</li>
<li class="listitem">
Added support for the <code class="computeroutput">fork()</code> system call. Programs that use
<code class="computeroutput">fork()</code> must call <code class="computeroutput">io_service.notify_fork()</code> at
the appropriate times. Two new examples have been added showing how to
use this feature.
</li>
<li class="listitem">
Cleaned up the handling of errors reported by the <code class="computeroutput">close()</code>
system call. In particular, assume that most operating systems won't have
<code class="computeroutput">close()</code> fail with <code class="computeroutput">EWOULDBLOCK</code>, but if it does
then set the blocking mode and restart the call. If any other error occurs,
assume the descriptor is closed.
</li>
<li class="listitem">
The kqueue flag <code class="computeroutput">EV_ONESHOT</code> seems to cause problems on some
versions of Mac OS X, with the <code class="computeroutput">io_service</code> destructor getting
stuck inside the <code class="computeroutput">close()</code> system call. Changed the kqueue backend
to use <code class="computeroutput">EV_CLEAR</code> instead.
</li>
<li class="listitem">
Changed exception reporting to include the function name in exception
<code class="computeroutput">what()</code> messages.
</li>
<li class="listitem">
Fixed an insufficient initialisers warning with MinGW.
</li>
<li class="listitem">
Changed the <code class="computeroutput">shutdown_service()</code> member functions to be private.
</li>
<li class="listitem">
Added archetypes for testing socket option functions.
</li>
<li class="listitem">
Added a missing lock in <code class="computeroutput">signal_set_service::cancel()</code>.
</li>
<li class="listitem">
Fixed a copy/paste error in <code class="computeroutput">SignalHandler</code> example.
</li>
<li class="listitem">
Added the inclusion of the signal header to <code class="computeroutput">signal_set_service.hpp</code>
so that constants like <code class="computeroutput">NSIG</code> may be used.
</li>
<li class="listitem">
Changed the <code class="computeroutput">signal_set_service</code> implementation so that it doesn't
assume that <code class="computeroutput">SIGRTMAX</code> is a compile-time constant.
</li>
<li class="listitem">
Changed the Boost.Asio examples so that they don't use Boost.Thread's convenience
header. Use the header file that is specifically for the boost::thread
class instead.
</li>
</ul></div>
<h4>
<a name="asio.history.h25"></a>
<span><a name="asio.history.asio_1_5_1"></a></span><a class="link" href="history.html#asio.history.asio_1_5_1">Asio
1.5.1</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added support for signal handling, using a new class called <code class="computeroutput">signal_set</code>.
Programs may add one or more signals to the set, and then perform an <code class="computeroutput">async_wait()</code>
operation. The specified handler will be called when one of the signals
occurs. The same signal number may registered with multiple <code class="computeroutput">signal_set</code>
objects, however the signal number must be used only with Asio.
</li>
<li class="listitem">
Added handler tracking, a new debugging aid. When enabled by defining
<code class="computeroutput">(BOOST_)ASIO_ENABLE_HANDLER_TRACKING</code>, Asio writes debugging
output to the standard error stream. The output records asynchronous operations
and the relationships between their handlers. It may be post-processed
using the included <code class="literal">handlerviz.pl</code> tool to create a visual
representation of the handlers (requires GraphViz).
</li>
<li class="listitem">
Fixed a bug in <code class="computeroutput">asio::streambuf</code> where the <code class="computeroutput">consume()</code>
function did not always update the internal buffer pointers correctly.
The problem may occur when the <code class="computeroutput">asio::streambuf</code> is filled with
data using the standard C++ member functions such as <code class="computeroutput">sputn()</code>.
(Note: the problem does not manifest when the streambuf is populated by
the Asio free functions <code class="computeroutput">read()</code>, <code class="computeroutput">async_read()</code>,
<code class="computeroutput">read_until()</code> or <code class="computeroutput">async_read_until()</code>.)
</li>
<li class="listitem">
Fixed a bug on kqueue-based platforms, where reactor read operations that
return false from their <code class="computeroutput">perform()</code> function are not correctly
re-registered with kqueue.
</li>
<li class="listitem">
Support for <code class="computeroutput">std::error_code</code> and <code class="computeroutput">std::system_error</code>
is no longer enabled by default for MSVC10, as that compiler's standard
library does not implement <code class="computeroutput">std::system_error::what()</code> correctly.
</li>
<li class="listitem">
Modified the <code class="computeroutput">buffers_iterator&lt;&gt;</code> and <code class="computeroutput">ip::basic_resolver_iterator</code>
classes so that the value_type typedefs are non-const byte types.
</li>
</ul></div>
<h4>
<a name="asio.history.h26"></a>
<span><a name="asio.history.asio_1_5_0"></a></span><a class="link" href="history.html#asio.history.asio_1_5_0">Asio
1.5.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added support for timeouts on socket iostreams, such as <code class="computeroutput">ip::tcp::iostream</code>.
A timeout is set by calling <code class="computeroutput">expires_at()</code> or <code class="computeroutput">expires_from_now()</code>
to establish a deadline. Any socket operations which occur past the deadline
will put the iostream into a bad state.
</li>
<li class="listitem">
Added a new <code class="computeroutput">error()</code> member function to socket iostreams, for
retrieving the error code from the most recent system call.
</li>
<li class="listitem">
Added a new <code class="computeroutput">basic_deadline_timer::cancel_one()</code> function. This
function lets you cancel a single waiting handler on a timer. Handlers
are cancelled in FIFO order.
</li>
<li class="listitem">
Added a new <code class="computeroutput">transfer_exactly()</code> completion condition. This
can be used to send or receive a specified number of bytes even if the
total size of the buffer (or buffer sequence) is larger.
</li>
<li class="listitem">
Added new free functions <code class="computeroutput">connect()</code> and <code class="computeroutput">async_connect()</code>.
These operations try each endpoint in a list until the socket is successfully
connected.
</li>
<li class="listitem">
Extended the <code class="computeroutput">buffer_size()</code> function so that it works for buffer
sequences in addition to individual buffers.
</li>
<li class="listitem">
Added a new <code class="computeroutput">buffer_copy()</code> function that can be used to copy
the raw bytes between individual buffers and buffer sequences.
</li>
<li class="listitem">
Added new non-throwing overloads of <code class="computeroutput">read()</code>, <code class="computeroutput">read_at()</code>,
<code class="computeroutput">write()</code> and <code class="computeroutput">write_at()</code> that do not require a
completion condition.
</li>
<li class="listitem">
Added friendlier compiler errors for when a completion handler does not
meet the necessary type requirements. When C++0x is available (currently
supported for g++ 4.5 or later, and MSVC 10), <code class="computeroutput">static_assert</code>
is also used to generate an informative error message. This checking may
be disabled by defining <code class="computeroutput">(BOOST_)ASIO_DISABLE_HANDLER_TYPE_REQUIREMENTS</code>.
</li>
<li class="listitem">
Added support for using <code class="computeroutput">std::error_code</code> and <code class="computeroutput">std::system_error</code>,
when available. The support is automatically enabled when compiling in
<code class="literal">-std=c++0x</code> mode on g++ 4.5 or higher, or when using
MSVC 10. The support may be explicitly enabled by defining <code class="computeroutput">ASIO_HAS_STD_SYSTEM_ERROR</code>,
or disabled by defining <code class="computeroutput">ASIO_DISABLE_STD_SYSTEM_ERROR</code>. (Available
in non-Boost version of Asio only.)
</li>
<li class="listitem">
Made the <code class="computeroutput">is_loopback()</code>, <code class="computeroutput">is_unspecified()</code> and
<code class="computeroutput">is_multicast()</code> functions consistently available across the
<code class="computeroutput">ip::address</code>, <code class="computeroutput">ip::address_v4</code> and <code class="computeroutput">ip::address_v6</code>
classes.
</li>
<li class="listitem">
Added new <code class="computeroutput">non_blocking()</code> functions for managing the non-blocking
behaviour of a socket or descriptor. The <code class="computeroutput">io_control()</code> commands
named <code class="computeroutput">non_blocking_io</code> are now deprecated in favour of these
new functions.
</li>
<li class="listitem">
Added new <code class="computeroutput">native_non_blocking()</code> functions for managing the
non-blocking mode of the underlying socket or descriptor. These functions
are intended to allow the encapsulation of arbitrary non-blocking system
calls as asynchronous operations, in a way that is transparent to the user
of the socket object. The functions have no effect on the behaviour of
the synchronous operations of the socket or descriptor.
</li>
<li class="listitem">
Added the <code class="computeroutput">io_control()</code> member function for socket acceptors.
</li>
<li class="listitem">
For consistency with the C++0x standard library, deprecated the <code class="computeroutput">native_type</code>
typedefs in favour of <code class="computeroutput">native_handle_type</code>, and the <code class="computeroutput">native()</code>
member functions in favour of <code class="computeroutput">native_handle()</code>.
</li>
<li class="listitem">
Added a <code class="computeroutput">release()</code> member function to posix descriptors. This
function releases ownership of the underlying native descriptor to the
caller.
</li>
<li class="listitem">
Added support for sequenced packet sockets (<code class="computeroutput">SOCK_SEQPACKET</code>).
</li>
<li class="listitem">
Added a new <code class="computeroutput">io_service::stopped()</code> function that can be used
to determine whether the <code class="computeroutput">io_service</code> has stopped (i.e. a <code class="computeroutput">reset()</code>
call is needed prior to any further calls to <code class="computeroutput">run()</code>, <code class="computeroutput">run_one()</code>,
<code class="computeroutput">poll()</code> or <code class="computeroutput">poll_one()</code>).
</li>
<li class="listitem">
Reduced the copying of handler function objects.
</li>
<li class="listitem">
Added support for C++0x move construction to further reduce copying of
handler objects. Move support is enabled when compiling in <code class="literal">-std=c++0x</code>
mode on g++ 4.5 or higher, or when using MSVC10.
</li>
<li class="listitem">
Removed the dependency on OS-provided macros for the well-known IPv4 and
IPv6 addresses. This should eliminate the annoying "missing braces
around initializer" warnings.
</li>
<li class="listitem">
Reduced the size of <code class="computeroutput">ip::basic_endpoint&lt;&gt;</code> objects (such
as <code class="computeroutput">ip::tcp::endpoint</code> and <code class="computeroutput">ip::udp::endpoint</code>).
</li>
<li class="listitem">
Changed the reactor backends to assume that any descriptors or sockets
added using <code class="computeroutput">assign()</code> may have been <code class="computeroutput">dup()</code>-ed,
and so require explicit deregistration from the reactor.
</li>
<li class="listitem">
Changed the SSL error category to return error strings from the OpenSSL
library.
</li>
<li class="listitem">
Changed the separate compilation support such that, to use Asio's SSL capabilities,
you should also include 'asio/ssl/impl/src.hpp` in one source file in your
program.
</li>
<li class="listitem">
Removed the deprecated member functions named <code class="computeroutput">io_service()</code>.
The <code class="computeroutput">get_io_service()</code> member functions should be used instead.
</li>
<li class="listitem">
Removed the deprecated typedefs <code class="computeroutput">resolver_query</code> and <code class="computeroutput">resolver_iterator</code>
from the <code class="computeroutput">ip::tcp</code>, <code class="computeroutput">ip::udp</code> and <code class="computeroutput">ip::icmp</code>
classes.
</li>
<li class="listitem">
Fixed a compile error on some versions of g++ due to anonymous enums.
</li>
<li class="listitem">
Added an explicit cast to the <code class="computeroutput">FIONBIO</code> constant to int to suppress
a compiler warning on some platforms.
</li>
<li class="listitem">
Fixed warnings reported by g++'s <code class="literal">-Wshadow</code> compiler option.
</li>
</ul></div>
<h4>
<a name="asio.history.h27"></a>
<span><a name="asio.history.asio_1_4_8"></a></span><a class="link" href="history.html#asio.history.asio_1_4_8">Asio
1.4.8</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Fixed an integer overflow problem that occurs when <code class="computeroutput">ip::address_v4::broadcast()</code>
is used on 64-bit platforms.
</li>
<li class="listitem">
Fixed a problem on older Linux kernels (where epoll is used without <code class="computeroutput">timerfd</code>
support) that prevents timely delivery of <code class="computeroutput">deadline_timer</code> handlers,
after the program has been running for some time.
</li>
</ul></div>
<h4>
<a name="asio.history.h28"></a>
<span><a name="asio.history.asio_1_4_7"></a></span><a class="link" href="history.html#asio.history.asio_1_4_7">Asio
1.4.7</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Fixed a problem on kqueue-based platforms where a <code class="computeroutput">deadline_timer</code>
may never fire if the <code class="computeroutput">io_service</code> is running in a background
thread.
</li>
<li class="listitem">
Fixed a const-correctness issue that prevented valid uses of <code class="computeroutput">has_service&lt;&gt;</code>
from compiling.
</li>
<li class="listitem">
Fixed MinGW cross-compilation.
</li>
<li class="listitem">
Removed dependency on deprecated Boost.System functions (Boost.Asio only).
</li>
<li class="listitem">
Ensured <code class="computeroutput">close()</code>/<code class="computeroutput">closesocket()</code> failures are correctly
propagated.
</li>
<li class="listitem">
Added a check for errors returned by <code class="computeroutput">InitializeCriticalSectionAndSpinCount</code>.
</li>
<li class="listitem">
Added support for hardware flow control on QNX.
</li>
<li class="listitem">
Always use <code class="computeroutput">pselect()</code> on HP-UX, if it is available.
</li>
<li class="listitem">
Ensured handler arguments are passed as lvalues.
</li>
<li class="listitem">
Fixed Windows build when thread support is disabled.
</li>
<li class="listitem">
Fixed a Windows-specific problem where <code class="computeroutput">deadline_timer</code> objects
with expiry times set more than 5 minutes in the future may never expire.
</li>
<li class="listitem">
Fixed the resolver backend on BSD platforms so that an empty service name
resolves to port number <code class="computeroutput">0</code>, as per the documentation.
</li>
<li class="listitem">
Fixed read operations so that they do not accept buffer sequences of type
<code class="computeroutput">const_buffers_1</code>.
</li>
<li class="listitem">
Redefined <code class="computeroutput">Protocol</code> and <code class="computeroutput">id</code> to avoid clashing with
Objective-C++ keywords.
</li>
<li class="listitem">
Fixed a <code class="computeroutput">vector</code> reallocation performance issue that can occur
when there are many active <code class="computeroutput">deadline_timer</code> objects.
</li>
<li class="listitem">
Fixed the kqueue backend so that it compiles on NetBSD.
</li>
<li class="listitem">
Fixed the socket <code class="computeroutput">io_control()</code> implementation on 64-bit Mac
OS X and BSD platforms.
</li>
<li class="listitem">
Fixed a Windows-specific problem where failures from <code class="computeroutput">accept()</code>
are incorrectly treated as successes.
</li>
<li class="listitem">
Deprecated the separate compilation header <code class="computeroutput">asio/impl/src.cpp</code>
in favour of <code class="computeroutput">asio/impl/src.hpp</code>.
</li>
</ul></div>
<h4>
<a name="asio.history.h29"></a>
<span><a name="asio.history.asio_1_4_6"></a></span><a class="link" href="history.html#asio.history.asio_1_4_6">Asio
1.4.6</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Reduced compile times. (Note that some programs may need to add additional
<code class="computeroutput">#include</code>s, e.g. if the program uses boost::array but does
not explicitly include <code class="computeroutput">&lt;boost/array.hpp&gt;</code>.)
</li>
<li class="listitem">
Reduced the size of generated code.
</li>
<li class="listitem">
Refactored <code class="computeroutput">deadline_timer</code> implementation to improve performance.
</li>
<li class="listitem">
Improved multiprocessor scalability on Windows by using a dedicated hidden
thread to wait for timers.
</li>
<li class="listitem">
Improved performance of <code class="computeroutput">asio::streambuf</code> with <code class="computeroutput">async_read()</code>
and <code class="computeroutput">async_read_until()</code>. These read operations now use the
existing capacity of the <code class="computeroutput">streambuf</code> when reading, rather than
limiting the read to 512 bytes.
</li>
<li class="listitem">
Added optional separate compilation. To enable, include <code class="computeroutput">asio/impl/src.cpp</code>
in one source file in a program, then build the program with <code class="computeroutput">(BOOST_)ASIO_SEPARATE_COMPILATION</code>
defined in the project/compiler settings. Alternatively, <code class="computeroutput">(BOOST_)ASIO_DYN_LINK</code>
may be defined to build a separately-compiled Asio as part of a shared
library.
</li>
<li class="listitem">
Added new macro <code class="computeroutput">(BOOST_)ASIO_DISABLE_FENCED_BLOCK</code> to permit
the disabling of memory fences around completion handlers, even if thread
support is enabled.
</li>
<li class="listitem">
Reworked timeout examples to better illustrate typical use cases.
</li>
<li class="listitem">
Ensured that handler arguments are passed as const types.
</li>
<li class="listitem">
Fixed incorrect parameter order in <code class="computeroutput">null_buffers</code> variant of
<code class="computeroutput">async_send_to</code>.
</li>
<li class="listitem">
Ensured unsigned char is used with <code class="computeroutput">isdigit</code> in <code class="computeroutput">getaddrinfo</code>
emulation.
</li>
<li class="listitem">
Fixed handling of very small but non-zero timeouts.
</li>
<li class="listitem">
Fixed crash that occurred when an empty buffer sequence was passed to a
composed read or write operation.
</li>
<li class="listitem">
Added missing operator+ overload in <code class="computeroutput">buffers_iterator</code>.
</li>
<li class="listitem">
Implemented cancellation of <code class="computeroutput">null_buffers</code> operations on Windows.
</li>
</ul></div>
<h4>
<a name="asio.history.h30"></a>
<span><a name="asio.history.asio_1_4_5"></a></span><a class="link" href="history.html#asio.history.asio_1_4_5">Asio
1.4.5</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Improved performance.
</li>
<li class="listitem">
Reduced compile times.
</li>
<li class="listitem">
Reduced the size of generated code.
</li>
<li class="listitem">
Extended the guarantee that background threads don't call user code to
all asynchronous operations.
</li>
<li class="listitem">
Changed to use edge-triggered epoll on Linux.
</li>
<li class="listitem">
Changed to use <code class="computeroutput">timerfd</code> for dispatching timers on Linux, when
available.
</li>
<li class="listitem">
Changed to use one-shot notifications with kqueue on Mac OS X and BSD platforms.
</li>
<li class="listitem">
Added a bitmask type <code class="computeroutput">ip::resolver_query_base::flags</code> as per
the TR2 proposal. This type prevents implicit conversion from <code class="computeroutput">int</code>
to <code class="computeroutput">flags</code>, allowing the compiler to catch cases where users
incorrectly pass a numeric port number as the service name.
</li>
<li class="listitem">
Added <code class="computeroutput">#define NOMINMAX</code> for all Windows compilers. Users can
define <code class="computeroutput">(BOOST_)ASIO_NO_NOMINMAX</code> to suppress this definition.
</li>
<li class="listitem">
Fixed a bug where 0-byte asynchronous reads were incorrectly passing an
<code class="computeroutput">error::eof</code> result to the completion handler.
</li>
<li class="listitem">
Changed the <code class="computeroutput">io_control()</code> member functions to always call
<code class="computeroutput">ioctl</code> on the underlying descriptor when modifying blocking
mode.
</li>
<li class="listitem">
Changed the resolver implementation so that it no longer requires the typedefs
<code class="computeroutput">InternetProtocol::resolver_query</code> and <code class="computeroutput">InternetProtocol::resolver_iterator</code>,
as neither typedef is part of the documented <code class="computeroutput">InternetProtocol</code>
requirements. The corresponding typedefs in the <code class="computeroutput">ip::tcp</code>,
<code class="computeroutput">ip::udp</code> and <code class="computeroutput">ip::icmp</code> classes have been deprecated.
</li>
<li class="listitem">
Fixed out-of-band handling for reactors not based on <code class="computeroutput">select()</code>.
</li>
<li class="listitem">
Added new <code class="computeroutput">(BOOST_)ASIO_DISABLE_THREADS</code> macro that allows Asio's
threading support to be independently disabled.
</li>
<li class="listitem">
Minor documentation improvements.
</li>
</ul></div>
<h4>
<a name="asio.history.h31"></a>
<span><a name="asio.history.asio_1_4_4"></a></span><a class="link" href="history.html#asio.history.asio_1_4_4">Asio
1.4.4</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added a new HTTP Server 4 example illustrating the use of stackless coroutines
with Asio.
</li>
<li class="listitem">
Changed handler allocation and invocation to use <code class="computeroutput">boost::addressof</code>
to get the address of handler objects, rather than applying <code class="computeroutput">operator&amp;</code>
directly.
</li>
<li class="listitem">
Restricted MSVC buffer debugging workaround to 2008, as it causes a crash
with 2010 beta 2.
</li>
<li class="listitem">
Fixed a problem with the lifetime of handler memory, where Windows needs
the <code class="computeroutput">OVERLAPPED</code> structure to be valid until both the initiating
function call has returned and the completion packet has been delivered.
</li>
<li class="listitem">
Don't block signals while performing system calls, but instead restart
the calls if they are interrupted.
</li>
<li class="listitem">
Documented the guarantee made by strand objects with respect to order of
handler invocation.
</li>
<li class="listitem">
Changed strands to use a pool of implementations, to make copying of strands
cheaper.
</li>
<li class="listitem">
Ensured that kqueue support is enabled for BSD platforms.
</li>
<li class="listitem">
Added a <code class="computeroutput">boost_</code> prefix to the <code class="computeroutput">extern "C"</code>
thread entry point function.
</li>
<li class="listitem">
In <code class="computeroutput">getaddrinfo</code> emulation, only check the socket type (<code class="computeroutput">SOCK_STREAM</code>
or <code class="computeroutput">SOCK_DGRAM</code>) if a service name has been specified. This
should allow the emulation to work with raw sockets.
</li>
<li class="listitem">
Added a workaround for some broken Windows firewalls that make a socket
appear bound to 0.0.0.0 when it is in fact bound to 127.0.0.1.
</li>
<li class="listitem">
Applied a fix for reported excessive CPU usage under Solaris.
</li>
<li class="listitem">
Added some support for platforms that use older compilers such as g++ 2.95.
</li>
</ul></div>
<h4>
<a name="asio.history.h32"></a>
<span><a name="asio.history.asio_1_4_3"></a></span><a class="link" href="history.html#asio.history.asio_1_4_3">Asio
1.4.3</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added a new ping example to illustrate the use of ICMP sockets.
</li>
<li class="listitem">
Changed the <code class="computeroutput">buffered*_stream&lt;&gt;</code> templates to treat 0-byte
reads and writes as no-ops, to comply with the documented type requirements
for <code class="computeroutput">SyncReadStream</code>, <code class="computeroutput">AsyncReadStream</code>, <code class="computeroutput">SyncWriteStream</code>
and <code class="computeroutput">AsyncWriteStream</code>.
</li>
<li class="listitem">
Changed some instances of the <code class="computeroutput">throw</code> keyword to <code class="computeroutput">boost::throw_exception()</code>
to allow Asio to be used when exception support is disabled. Note that
the SSL wrappers still require exception support.
</li>
<li class="listitem">
Made Asio compatible with the OpenSSL 1.0 beta.
</li>
<li class="listitem">
Eliminated a redundant system call in the Solaris /dev/poll backend.
</li>
<li class="listitem">
Fixed a bug in resizing of the bucket array in the internal hash maps.
</li>
<li class="listitem">
Ensured correct propagation of the error code when a synchronous accept
fails.
</li>
<li class="listitem">
Ensured correct propagation of the error code when a synchronous read or
write on a Windows <code class="computeroutput">HANDLE</code> fails.
</li>
<li class="listitem">
Fixed failures reported when <code class="computeroutput">_GLIBCXX_DEBUG</code> is defined.
</li>
<li class="listitem">
Fixed custom memory allocation support for timers.
</li>
<li class="listitem">
Tidied up various warnings reported by g++.
</li>
<li class="listitem">
Various documentation improvements, including more obvious hyperlinks to
function overloads, header file information, examples for the handler type
requirements, and adding enum values to the index.
</li>
</ul></div>
<h4>
<a name="asio.history.h33"></a>
<span><a name="asio.history.asio_1_4_2"></a></span><a class="link" href="history.html#asio.history.asio_1_4_2">Asio
1.4.2</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Implement automatic resizing of the bucket array in the internal hash maps.
This is to improve performance for very large numbers of asynchronous operations
and also to reduce memory usage for very small numbers. A new macro <code class="computeroutput">(BOOST_)ASIO_HASH_MAP_BUCKETS</code>
may be used to tweak the sizes used for the bucket arrays. (N.B. this feature
introduced a bug which was fixed in Asio 1.4.3 / Boost 1.40.)
</li>
<li class="listitem">
Add performance optimisation for the Windows IOCP backend for when no timers
are used.
</li>
<li class="listitem">
Prevent locale settings from affecting formatting of TCP and UDP endpoints.
</li>
<li class="listitem">
Fix a memory leak that occurred when an asynchronous SSL operation's completion
handler threw an exception.
</li>
<li class="listitem">
Fix the implementation of <code class="computeroutput">io_control()</code> so that it adheres
to the documented type requirements for IoControlCommand.
</li>
<li class="listitem">
Fix incompatibility between Asio and ncurses.h.
</li>
<li class="listitem">
On Windows, specifically handle the case when an overlapped <code class="computeroutput">ReadFile</code>
call fails with <code class="computeroutput">ERROR_MORE_DATA</code>. This enables a hack where
a <code class="computeroutput">windows::stream_handle</code> can be used with a message-oriented
named pipe.
</li>
<li class="listitem">
Fix system call wrappers to always clear the error on success, as POSIX
allows successful system calls to modify errno.
</li>
<li class="listitem">
Don't include termios.h if <code class="computeroutput">(BOOST_)ASIO_DISABLE_SERIAL_PORT</code>
is defined.
</li>
<li class="listitem">
Cleaned up some more MSVC level 4 warnings.
</li>
<li class="listitem">
Various documentation fixes.
</li>
</ul></div>
<h4>
<a name="asio.history.h34"></a>
<span><a name="asio.history.asio_1_4_1"></a></span><a class="link" href="history.html#asio.history.asio_1_4_1">Asio
1.4.1</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Improved compatibility with some Windows firewall software.
</li>
<li class="listitem">
Ensured arguments to <code class="computeroutput">windows::overlapped_ptr::complete()</code> are
correctly passed to the completion handler.
</li>
<li class="listitem">
Fixed a link problem and multicast failure on QNX.
</li>
<li class="listitem">
Fixed a compile error in SSL support on MinGW / g++ 3.4.5.
</li>
<li class="listitem">
Drop back to using a pipe for notification if eventfd is not available
at runtime on Linux.
</li>
<li class="listitem">
Various minor bug and documentation fixes.
</li>
</ul></div>
<h4>
<a name="asio.history.h35"></a>
<span><a name="asio.history.asio_1_4_0"></a></span><a class="link" href="history.html#asio.history.asio_1_4_0">Asio
1.4.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Enhanced CompletionCondition concept with the signature <code class="computeroutput">size_t CompletionCondition(error_code
ec, size_t total)</code>, where the return value indicates the maximum
number of bytes to be transferred on the next read or write operation.
(The old CompletionCondition signature is still supported for backwards
compatibility).
</li>
<li class="listitem">
New <code class="computeroutput">windows::overlapped_ptr</code> class to allow arbitrary overlapped
I/O functions (such as <code class="computeroutput">TransmitFile</code>) to be used with Asio.
</li>
<li class="listitem">
On recent versions of Linux, an <code class="computeroutput">eventfd</code> descriptor is now
used (rather than a pipe) to interrupt a blocked select/epoll reactor.
</li>
<li class="listitem">
Added const overloads of <code class="computeroutput">lowest_layer()</code>.
</li>
<li class="listitem">
Synchronous read, write, accept and connect operations are now thread safe
(meaning that it is now permitted to perform concurrent synchronous operations
on an individual socket, if supported by the OS).
</li>
<li class="listitem">
Reactor-based <code class="computeroutput">io_service</code> implementations now use lazy initialisation
to reduce the memory usage of an <code class="computeroutput">io_service</code> object used only
as a message queue.
</li>
</ul></div>
<h4>
<a name="asio.history.h36"></a>
<span><a name="asio.history.asio_1_2_0"></a></span><a class="link" href="history.html#asio.history.asio_1_2_0">Asio
1.2.0</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Added support for serial ports.
</li>
<li class="listitem">
Added support for UNIX domain sockets.
</li>
<li class="listitem">
Added support for raw sockets and ICMP.
</li>
<li class="listitem">
Added wrappers for POSIX stream-oriented file descriptors (excluding regular
files).
</li>
<li class="listitem">
Added wrappers for Windows stream-oriented <code class="computeroutput">HANDLE</code>s such as
named pipes (requires <code class="computeroutput">HANDLE</code>s that work with I/O completion
ports).
</li>
<li class="listitem">
Added wrappers for Windows random-access <code class="computeroutput">HANDLE</code>s such as files
(requires <code class="computeroutput">HANDLE</code>s that work with I/O completion ports).
</li>
<li class="listitem">
Added support for reactor-style operations (i.e. they report readiness
but perform no I/O) using a new <code class="computeroutput">null_buffers</code> type.
</li>
<li class="listitem">
Added an iterator type for bytewise traversal of buffer sequences.
</li>
<li class="listitem">
Added new <code class="computeroutput">read_until()</code> and <code class="computeroutput">async_read_until()</code>
overloads that take a user-defined function object for locating message
boundaries.
</li>
<li class="listitem">
Added an experimental two-lock queue (enabled by defining <code class="computeroutput">(BOOST_)ASIO_ENABLE_TWO_LOCK_QUEUE</code>)
that may provide better <code class="computeroutput">io_service</code> scalability across many
processors.
</li>
<li class="listitem">
Various fixes, performance improvements, and more complete coverage of
the custom memory allocation support.
</li>
</ul></div>
<h4>
<a name="asio.history.h37"></a>
<span><a name="asio.history.asio_1_0_0"></a></span><a class="link" href="history.html#asio.history.asio_1_0_0">Asio
1.0.0</a>
</h4>
<p>
First stable release of Asio.
</p>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M.
Kohlhoff<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
</p>
</div></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="std_executors.html"><img src="../prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../home.png" alt="Home"></a><a accesskey="n" href="index.html"><img src="../next.png" alt="Next"></a>
</div>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink