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diff --git a/erts/doc/src/notes.xml b/erts/doc/src/notes.xml index 1f372823e8..c9316d644c 100644 --- a/erts/doc/src/notes.xml +++ b/erts/doc/src/notes.xml @@ -31,6 +31,570 @@ </header> <p>This document describes the changes made to the ERTS application.</p> +<section><title>Erts 14.0</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>If a local fun was called while reloading the + <em>exact same</em> module that defined said fun, there + was a small window in which the call would land in code + that was yet to be fully loaded.</p> + <p> + Own Id: OTP-18016</p> + </item> + <item> + <p> + Fix the TLS distribution to work when starting Erlang in + embedded mode and a connection is done before kernel is + fully started.</p> + <p> + Own Id: OTP-18248 Aux Id: PR-6227 GH-6085 </p> + </item> + <item> + <p> + erl <c>-remsh</c> has been improved to provide better + error reasons and work when using a shell without + terminal support (that is an "oldshell").</p> + <p> + Own Id: OTP-18271 Aux Id: PR-6279 </p> + </item> + <item> + <p> + Fix so that <c>-fno-omit-frame-pointer</c> is applied to + all of the Erlang VM when using the JIT so that tools, + such as perf, can crawl the process stacks.</p> + <p> + Own Id: OTP-18274 Aux Id: PR-6048 </p> + </item> + <item> + <p> + Compilation server now support unicode paths in + compilation server for filesystems that are encoded with + unicode.</p> + <p> + Own Id: OTP-18277 Aux Id: PR-6306 </p> + </item> + <item> + <p>Reintroduced the optimization that turned anonymous + functions without free variables into literals + (OTP-15195). This optimization was lost during + refactoring in OTP 24.</p> <p>Alongside this fix, we plan + to remove the "fun creator pid" feature in OTP 27. See + <seeguide + marker="system/general_info:upcoming_incompatibilities#fun_creator_pid">Upcoming + Potential Incompatibilities</seeguide> for more + details.</p> + <p> + Own Id: OTP-18498</p> + </item> + <item> + <p>Fixed a crash during tracing on certain platforms that + cannot use the machine stack for Erlang code (mainly + OpenBSD and Linux with musl).</p> + <p> + Own Id: OTP-18561</p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p> + The <seecref + marker="erts:erl_nif#enif_set_option"><c>enif_set_option()</c></seecref> + function has been introduced into the NIF API. It can be + used in order to set the <seecref + marker="erts:erl_nif#delay_halt"><c>ERL_NIF_OPT_DELAY_HALT</c></seecref> + and/or <seecref + marker="erts:erl_nif#on_halt"><c>ERL_NIF_OPT_ON_HALT</c></seecref> + options with which one can synchronize halt of the + runtime system with flushing enabled and execution of + NIFs. <seemfa marker="erts:erlang#halt/2">Halt of the + runtime system <i>without</i> flushing enabled</seemfa>, + now terminates the runtime system without execution of + <c>atexit</c>/<c>on_exit</c> handlers that may have been + installed into the runtime system which might be + considered a potential incompatibility.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-17771 Aux Id: GH-5325, PR-6370 </p> + </item> + <item> + <p>The TTY/terminal subsystem has been rewritten by + moving more code to Erlang from the old linked-in driver + and implementing all the I/O primitives needed in a NIF + instead. </p><p> On Unix platforms the user should not + notice a lot of difference, besides better handling of + unicode characters and fixing of some long standing bugs. + </p><p> Windows users will notice that erl.exe has the + same functionality as a normal Unix shell and that + werl.exe has been removed and replaced with a symlink to + erl.exe. This makes the Windows Erlang terminal + experience identical to that of Unix. </p><p> The + re-write brings with it a number of bug fixes and feature + additions:</p> <list> <item>The TTY is now reset when + Erlang exits, fixing zsh to not break when terminating an + Erlang session.</item> <item><c>standard_error</c> now + uses the same unicode mode as <c>standard_io</c>.</item> + <item>Hitting backspace when searching the shell history + with an empty search string no longer breaks the + shell.</item> <item>Tab expansion now works on remote + nodes started using the JCL interface.</item> <item>It is + now possible to configure the shell slogan and the + session slogans (that is the texts that appear when you + start an Erlang shell). See the kernel documentation for + more details.</item> <item>Added shell:start_interactive + for starting the interactive shell from a non-interactive + Erlang session (for example an escript).</item> <item>On + Windows, when starting in detached mode the standard + handler are now set to <c>nul</c> devices instead of + being unset.</item> <item> Standard I/O now always + defaults to <c>unicode</c> mode if supported. Previously + the default was <c>latin1</c> if the runtime system had + been started with <c>-oldshell</c> or <c>-noshell</c> + (for example in an <c>escript</c>). To send raw bytes + over standard out, one now explicitly has to specify + <c>io:setopts(standard_io, [{encoding, latin1}]).</c> + </item> </list> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-17932 Aux Id: PR-6144 GH-3150 GH-3390 GH-4343 + GH-4225 </p> + </item> + <item> + <p>Add support for socket on Windows.</p> <list> + <item>Pre release status.</item> <item>Error codes not + finalized.</item> <item>No explicit support for Windows + specific options (socket options, flags for read and + write).</item> <item>New async api for Windows + (completion). See the <c>Asynchronous calls</c> chapter + in the (Socket Usage) Users Guide.</item> <item>To ensure + platform independence, gen_tcp and gen_udp is + <em>intended</em> to be used (not yet updated).</item> + </list> + <p> + Own Id: OTP-18029</p> + </item> + <item> + <p> + Updated configure cache for Windows. This makes configure + run faster on Windows as many more checks are cached.</p> + <p> + Own Id: OTP-18053 Aux Id: PR-6101 </p> + </item> + <item> + <p>Optimized record updates.</p> + <p> + Own Id: OTP-18126 Aux Id: PR-6033 </p> + </item> + <item> + <p>Optimized internal hash routines.</p> + <p> + Own Id: OTP-18131</p> + </item> + <item> + <p> As announced when OTP 25 was released, <seeguide + marker="erts:time_correction#Multi_Time_Warp_Mode">multi + time warp mode</seeguide> is now enabled by default. This + assumes that all code executing on the system is + <seeguide + marker="erts:time_correction#Time_Warp_Safe_Code">time + warp safe</seeguide>. </p> <p> If you have old code in + the system that is not time warp safe, you now explicitly + need to start the system in <seeguide + marker="erts:time_correction#No_Time_Warp_Mode">no time + warp mode</seeguide> (or <seeguide + marker="erts:time_correction#Single_Time_Warp_Mode">singe + time warp mode</seeguide> if it is partially time warp + safe) in order to avoid problems. When starting the + system in no time warp mode, the system behaves as it did + prior to the introduction of the extended time + functionality introduced in OTP 18. </p> <p> If you have + code that is not time warp safe, you are strongly + encouraged to change this so that you can use multi time + warp mode. Compared to no time warp mode, multi time warp + mode improves scalability and performance as well as + accuracy and precision of time measurements. </p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-18135 Aux Id: GH-4965, PR-6046 </p> + </item> + <item> + <p>There are several new optimization for binary syntax + in the JIT:</p> <list> <item>Creation and matching of + binaries with segments of fixed sizes have been + optimized.</item> <item>Creation and matching of UTF-8 + segments have been optimized.</item> <item>Appending to + binaries has been optimized.</item> </list> + <p> + Own Id: OTP-18137 Aux Id: PR-6259, PR-6404, PR-6576, + PR-6804 </p> + </item> + <item> + <p>As announced since the release of OTP 24, support + for:</p> <list> <item><p> version 4 node container types + in the external term format are now mandatory. That is, + references supporting up to 5 32-bit integer identifiers, + and process and port identifiers with support for 64-bit + data storage. The distribution flag <seeguide + marker="erts:erl_dist_protocol#DFLAG_V4_NC"><c>DFLAG_V4_NC</c></seeguide> + is therefor now also mandatory. OTP has since OTP 24 + supported this. Also note that the external format + produced by <c>term_to_binary()</c> and + <c>term_to_iovec()</c> will unconditionally produce pids, + ports, and references supporting this larger format. + </p></item> <item><p> the <seeguide + marker="erts:erl_dist_protocol#new_link_protocol">new + link protocol</seeguide> introduced in OTP 23.3 is now + mandatory. The distribution flag <seeguide + marker="erts:erl_dist_protocol#DFLAG_UNLINK_ID"><c>DFLAG_UNLINK_ID</c></seeguide> + is therefor now also mandatory. </p></item> </list> + <p>Due to the above, OTP 26 nodes will refuse to connect + to OTP nodes from releases prior to OTP 24.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-18140 Aux Id: PR-6072 </p> + </item> + <item> + <p>Optimization of <seeguide + marker="system/reference_manual:processes#process-aliases"><i>process + aliases</i></seeguide> made possible now that support for + <seeguide marker="erl_dist_protocol#DFLAG_V4_NC">version + 4 node container types</seeguide> in the external term + format is mandatory.</p> + <p> + Own Id: OTP-18141 Aux Id: OTP-18140, PR-6073 </p> + </item> + <item> + <p>The compiler and JIT now generate better code for + creation of small maps where all keys are literals known + at compile time.</p> + <p> + Own Id: OTP-18185 Aux Id: GH-6139 </p> + </item> + <item> + <p> + When <c>erl -eval</c> fails to execute a command, an + error description is printed to standard_error.</p> + <p> + Own Id: OTP-18227 Aux Id: PR-6254 </p> + </item> + <item> + <p>Support for UTF-8 atoms and strings in the NIF + interface including new functions + <c>enif_make_new_atom</c>, <c>enif_make_new_atom_len</c> + and <c>enif_get_string_length</c>.</p> + <p> + Own Id: OTP-18334 Aux Id: PR-6434 </p> + </item> + <item> + <p>The following <seemfa + marker="kernel:inet#setopts/2"><c>inet:setopts/2</c></seemfa> + options have been introduced:</p> <taglist> <tag><seeerl + marker="kernel:inet#option-reuseport"><c>reuseport</c></seeerl></tag> + <item><p>Reuse of local port. Load balancing may or may + not be provided depending on underlying OS.</p></item> + <tag><seeerl + marker="kernel:inet#option-reuseport_lb"><c>reuseport_lb</c></seeerl></tag> + <item><p>Reuse of local port. Load balancing + provided.</p></item> <tag><seeerl + marker="kernel:inet#option-exclusiveaddruse"><c>exclusiveaddruse</c></seeerl></tag> + <item><p>Exclusive address/port usage on Windows. This + socket option is Windows specific and will silently be + ignored on other systems.</p></item> </taglist> <p>The + behavior of setting <seeerl + marker="kernel:inet#option-reuseaddr"><c>reuseaddr</c></seeerl> + on Windows have changed in a <em>backwards + incompatible</em> way. The underlying <c>SO_REUSEADDR</c> + socket option is now only set if both the <c>reusaddr</c> + and the <c>reuseport</c> <c>inet</c> options have been + set. This since the underlying <c>SO_REUSEADDR</c> socket + option on Windows behaves similar to how BSD behaves if + both the underlying socket options <c>SO_REUSEADDR</c> + and <c>SO_REUSEPORT</c> have been set. See the + documentation of the <c>reuseaddr</c> option for more + information.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-18344 Aux Id: PR-6522, PR-6944, OTP-18324, + PR-6481, GH-6461 </p> + </item> + <item> + <p><c>erlang:display/1</c> will now print large maps in a + more readable way (similar to how small maps are + printed).</p> + <p> + Own Id: OTP-18360 Aux Id: PR-6497 </p> + </item> + <item> + <p>The BIFs <c>min/2</c> and <c>max/2</c> are now allowed + to be used in guards and match specs.</p> + <p> + Own Id: OTP-18367 Aux Id: GH-6544 </p> + </item> + <item> + <p> + Fail <c>enif_init_resource_type</c> and friends by + returning NULL if not called during load/upgrade. Old + behavior was undefined.</p> + <p> + Own Id: OTP-18369</p> + </item> + <item> + <p> + New option <c>include_shared_binaries</c> for the + <c>max_heap_size</c> process limit. If set to + <c>true</c>, large binaries (> 64 bytes), which may be + referred by several processes, are included in the memory + sum compared against the <c>max_heap_size</c> limit.</p> + <p> + Own Id: OTP-18410 Aux Id: GH-5889, PR-6345 </p> + </item> + <item> + <p>Map comprehensions as suggested in EEP 58 has now been + implemented.</p> + <p> + Own Id: OTP-18413 Aux Id: EEP-58, PR-6727 </p> + </item> + <item> + <p>Some map operations have been optimized by changing + the internal sort order of atom keys. This changes the + (undocumented) order of how atom keys in small maps are + printed and returned by <c>maps:to_list/1</c> and + <c>maps:next/1</c>. The new order is unpredictable and + may change between different invocations of the Erlang + VM.</p> + <p>For applications where order is important, there is a + new function <c>maps:iterator/2</c> for creating + iterators that return the map elements in a deterministic + order. There are also new modifiers <c>k</c> and <c>K</c> + for the format string for <c>io:format()</c> to support + printing map elements ordered.</p> + <p> + Own Id: OTP-18414 Aux Id: PR-6151 </p> + </item> + <item> + <p>Reduced memory usage of + <c>file:read_file_info/1,2</c></p> + <p> + Own Id: OTP-18424 Aux Id: PR-6716 </p> + </item> + <item> + <p>Add new function <c>current_stacktrace</c> for trace + match specifications used by + <c>erlang:trace_pattern/3</c>. </p><p> This new option + puts the current stacktrace of the caller into the trace + message sent to the trace receiver.</p> + <p> + Own Id: OTP-18425 Aux Id: PR-6628, GH-5333 </p> + </item> + <item> + <p> + The amount of significant bits in node local process + identifiers and port identifiers has been extended from + 28 bits to 60 bits on 64-bit runtime systems. This makes + these identifiers large enough to in practice never + having to be reused during the life time of a node.</p> + <p> + Own Id: OTP-18435 Aux Id: PR-6827 </p> + </item> + <item> + <p> + New trace feature <c>call_memory</c>. Similar to + <c>call_time</c> tracing, but instead of measure + accumulated time in traced functions it measures + accumulated heap space consumed by traced functions. It + can be used to compare how much different functions are + contributing to garbage collection being triggered.</p> + <p> + Own Id: OTP-18440 Aux Id: PR-6351 </p> + </item> + <item> + <p>It is no longer necessary to enable a feature in the + runtime system in order to load modules that are using + it. It is sufficient to enable the feature in the + compiler when compiling it.</p> + <p>That means that to use feature <c>maybe_expr</c> in + Erlang/OTP 26, it is sufficient to enable it during + compilation.</p> + <p>In Erlang/OTP 27, feature <c>maybe_expr</c> will be + enabled by default, but it will be possible to disable + it.</p> + <p> + Own Id: OTP-18445</p> + </item> + <item> + <p> Handling of <c>on_load</c> modules during boot has + been improved by adding an extra step in the boot order + for embedded mode that runs all <c>on_load</c> handlers, + instead of relying on explicit invocation of them, later, + when the kernel supervision tree starts. </p><p> This is + mostly a code improvement and OTP internal simplification + to avoid future bugs and to simplify code maintenance. + </p> + <p> + Own Id: OTP-18447</p> + </item> + <item> + <p> + Introduced the <seeerl + marker="erts:erlang#term_to_binary_local"><c>local</c></seeerl> + option of <seemfa + marker="erts:erlang#term_to_binary/2"><c>term_to_binary/2</c></seemfa> + and <seemfa + marker="erts:erlang#term_to_iovec/2"><c>term_to_iovec/2</c></seemfa>.</p> + <p> + Own Id: OTP-18477 Aux Id: PR-7006 </p> + </item> + <item> + <p> + Document the commonly used practice to create and store + static atoms at NIF load time in callbacks <c>load</c> or + <c>upgrade</c>.</p> + <p> + Own Id: OTP-18483 Aux Id: PR-6888 </p> + </item> + <item> + <p> + Optimize <c>ets:lookup_element</c> for uncompressed + tables by using a more efficient method to copy the term + from ETS to the heap of the calling process.</p> + <p> + Own Id: OTP-18493 Aux Id: PR-6272 </p> + </item> + <item> + <p>The default encoding of atoms by <c>term_to_binary</c> + and <c>term_to_iovec</c> have changed from Latin1 to + UTF-8. The old encoding can still be obtained with + options <c>{minor_version, 1}</c>.</p> <p>Apart from + encoding code points between 128 and 255 with two bytes + (UTF-8) instead of one, most atoms will occupy one less + byte as the length field use only one byte instead of two + if possible.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-18505 Aux Id: PR-6991 </p> + </item> + <item> + <p> + The version of zlib included in the Erlang/OTP source + code is now 1.2.13.</p> + <p> + Own Id: OTP-18517</p> + </item> + <item> + <p> + <c>gen_tcp:send/*</c>, <c>gen_udp:send/*</c> and + <c>gen_sctp:send/*</c> have been optimized to use the + infamous receive reference optimization, so now sending + should not have bad performance when the calling process + has a large message queue.</p> + <p> + Own Id: OTP-18520 Aux Id: GH-6455 </p> + </item> + <item> + <p>Added the new built-in type <c>dynamic()</c> + introduced in EEP-61, improving support for gradual type + checkers.</p> + <p> + Own Id: OTP-18522</p> + </item> + <item> + <p> + Optimize <c>maps:merge/2</c> memory consumption for small + maps (<33 keys) by reusing key tuples or entire maps + if the result map has the same number of keys as any of + the argument maps.</p> + <p> + Own Id: OTP-18523 Aux Id: PR-7004 </p> + </item> + <item> + <p> + Optimize <c>maps:merge/2</c> memory consumption further + for small maps by mutating 2nd map to use literal key + tuple of 1st map if both have the same keys.</p> + <p> + Own Id: OTP-18524 Aux Id: PR-7004, OTP-18523 </p> + </item> + <item> + <p><c>ceil/1</c>, <c>floor/1</c>, <c>is_bitstring/1</c>, + <c>is_boolean/1</c>, <c>is_function/2</c>, and + <c>tuple_size/1</c> can now be used in match + specifications.</p> + <p> + Own Id: OTP-18526 Aux Id: GH-7045 </p> + </item> + <item> + <p> + Allow IPv6 addresses as host in <c>http</c> packets + decoded by <c>erlang:decode_packet/3</c> and + <c>gen_tcp</c> packet option. The IPv6 address should be + enclosed within <c>[]</c> according to RFC2732.</p> + <p> + Own Id: OTP-18540 Aux Id: PR-6900 </p> + </item> + <item> + <p> + Removed the experimental <c>erts_alloc_config</c> module. + It no longer produced good configurations and cannot be + fixed in a reasonably backwards compatible manner. It has + since OTP 25 been deprecated and scheduled for removal in + OTP 26.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-18549 Aux Id: PR-7105 </p> + </item> + <item> + <p> + ERTS internal thread names have been changed. All threads + created by ERTS now have a prefix <c>erts_</c> followed + by a type name potentially followed by an integer index. + For example, normal schedulers are now named + <c>erts_sched_<IX></c>, dirty CPU schedulers + <c>erts_dcpus_<IX></c>, and dirty IO schedulers + <c>erts_dios_<IX></c>. NIF and driver thread names + are truncated at 15 characters regardless of whether the + underlying platform support more characters or not.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-18552 Aux Id: PR-6973 </p> + </item> + <item> + <p> + Further robustify implementation of large maps (> 32 + keys). Keys that happen to have same internal 32-bit hash + values are now put in collision nodes which are traversed + with linear search. This removes the demand for the + internal hash function when salted to eventually produce + different hashes for all possible pairs of unequal terms.</p> + <p> + Own Id: OTP-18569</p> + </item> + <item> + <p>In Erlang/OTP 27, <c>0.0</c> will no longer be + considered to be exactly equal to <c>-0.0</c>. See + <seeguide + marker="system/general_info:upcoming_incompatibilities#float_matching">Upcoming + Potential Incompatibilities</seeguide>.</p> + <p> + Own Id: OTP-18574</p> + </item> + </list> + </section> + +</section> + <section><title>Erts 13.2.2</title> <section><title>Fixed Bugs and Malfunctions</title> |