<div dir="ltr"><div dir="ltr"><h1>OTP 22 Release Candidate 2</h1>
<p>This is the second of three planned release candidates before the OTP 22 release.</p>
<p>The intention with this release is to get feedback from our users.
All feedback is welcome, even if it is only to say that it works for
you, as it lets us know that the release candidate got some testing.</p>
<p>Erlang/OTP 22 is a new major release with new features and improvements as well as incompatibilities.</p>
<h2>Potential Incompatibilities</h2>
<ul><li>gen_* behaviours: If logging of the last N messages through <span style="font-family:courier new,courier,monospace">sys:log/2,3</span> is active for the server, this log is included in the terminate report.</li><li>reltool: A new element, Opts, can now be included in a rel tuple in the reltool release specific configuration format: <span style="font-family:courier new,courier,monospace">{rel, Name, Vsn, RelApps, Opts}</span>.</li><li>All external pids/ports/refs created by <span style="font-family:courier new,courier,monospace">erlang:list_to_pid</span> and similar functions now compare equal to any other pid/port/ref with same number from that node.</li><li>The old legacy <span style="font-family:courier new,courier,monospace">erl_interface</span> library is deprecated as of OTP 22, and will be removed in OTP 23. This does not apply to the <span style="font-family:courier new,courier,monospace">ei</span> library.</li><li>VxWorks is deprecated as of OTP 22 and will be removed in OTP 23.</li></ul>
<h2>Additional highlights in release candidate 2</h2>
<ul><li>A simple socket API is provided through the <span style="font-family:courier new,courier,monospace">socket</span> module. This is a low level API that does *not* replace <span style="font-family:courier new,courier,monospace">gen_[tcp|udp|sctp]</span>.
It is intended to *eventually* replace the inet driver. It also
provides a basic API that facilitates the implementation of other
protocols than TCP, UDP and SCTP. Known issues are; No support for the
Windows OS (currently), a small term leakage. This feature will be
classed as experimental in OTP 22.</li><li>ssl: Basic support for TLS 1.3 Server for experimental use.</li><li>In OTP 22, HiPE (the native code compiler) is not fully functional.
The reasons for this are new BEAM instructions for binary matching that
the HiPE native code compiler does not support. If <span style="font-family:courier new,courier,monospace">erlc</span> is invoked with the <span style="font-family:courier new,courier,monospace">+native</span>
option, and if any of the new binary matching instructions are used,
the compiler will issue a warning and produce a BEAM file without native
code.</li><li>erts: Added the NIF function <span style="font-family:courier new,courier,monospace">enif_term_type</span>, which helps avoid long sequences of <span style="font-family:courier new,courier,monospace">enif_is_xyz</span>
by returning the type of the given term. This is especially helpful for
NIFs that serialize terms, such as JSON encoders, where it can improve
both performance and readability.</li><li>crypto: The new <span style="font-family:courier new,courier,monospace">hash_info/1</span> and <span style="font-family:courier new,courier,monospace">cipher_info/1</span> functions returns maps with information about the hash or cipher in the argument.</li></ul>
<h2>Highlights in release candidate 1</h2>
<h3>Erts:</h3>
<ul><li>Support for Erlang Distribution protocol to split the payload of large signals into several fragments.</li><li>ETS option write_concurrency now also effects and improves scalability of ordered_set tables.</li><li>The <span style="font-family:monospace,monospace">length/1</span> BIF used to calculate the length of the list in one go
without yielding, even if the list was very long. Now it yields when
called with long lists.</li><li>A new (still experimental) module <span style="font-family:courier new,courier,monospace">socket</span>
is introduced. It is implemented as a NIF and the idea is that it shall
be as "close as possible" to the OS level socket interface.</li></ul>
<h3>Compiler:</h3>
<ul><li>The compiler has been rewritten to internally use an intermediate
representation based on Static Single Assignment (SSA). The new
intermediate representation makes more optimizations possible.
<ul><li>The binary matching optimizations are now applicable in many more circumstances than before.</li><li>Type optimizations are now applied across local function calls, and will remove a lot more redundant type tests than before.</li></ul>
</li><li>All compiler options that can be given in the source file can now be given in the option list on the command line for <span style="font-family:monospace,monospace">erlc</span>.</li></ul>
<h3>Standard libraries:</h3>
<ul><li>Cover now uses the counters module instead of <span style="font-family:monospace,monospace">ets</span> for updating
counters. The new function <span style="font-family:monospace,monospace">cover:local_only/0 </span>allows running Cover in a
restricted but faster local-only mode. The increase in speed will vary
depending on the type of code being cover-compiled, as an example the
compiler test suite runs more than twice as fast with the new Cover.</li><li>SSL now uses the new logger API, including log levels and verbose debug logging.</li></ul>
<p>For more details see<br>
<a href="http://erlang.org/download/otp_src_22.0-rc2.readme">http://erlang.org/download/otp_src_22.0-rc2.readme</a></p>
<p>Pre built versions for Windows can be fetched here:<br>
<a href="http://erlang.org/download/otp_win32_22.0-rc2.exe">http://erlang.org/download/otp_win32_22.0-rc2.exe</a><br>
<a href="http://erlang.org/download/otp_win64_22.0-rc2.exe">http://erlang.org/download/otp_win64_22.0-rc2.exe</a></p>
<p>Online documentation can be browsed here:<br>
<a href="http://erlang.org/documentation/doc-11.0-rc2/doc">http://erlang.org/documentation/doc-11.0-rc2/doc</a></p>
<p>The Erlang/OTP source can also be found at GitHub on the official Erlang repository:</p>
<p><a href="https://github.com/erlang/otp">https://github.com/erlang/otp</a></p>
<p><a href="https://github.com/erlang/otp/releases/tag/OTP-22.0-rc2">OTP-22.0-rc2</a></p>
Thank you for all your contributions!</div></div>