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<title>Erts Release Notes</title>
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<center><h1>Erts Release Notes</h1></center>
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<!--- ################################################################# --->
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<!--- ----------------------------------------------------------------- --->
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<h3>Fixed errors and malfunctions</h3>
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The start_erl example script passed parameters to erlexec in an
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incorrect way; this is now corrected.<br>
39
Better error checking of invalid floating point numbers in
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The '{active,once}' option for <code>inet:setopts/2</code> is now
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An unneccessary garbage collection at process exit for processes with
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heap fragments is removed.<br>
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(Own Id: OTP-4603)<br>
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The script 'start' now spawns off an run_erl that's completely
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disconnected from the controlling terminal and that ignores sighup
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(Own Id: OTP-4612)<br>
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Some internal memory allocation routines (used in BIFs) would allocate
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more memory than necessary, especially if the default mininum heap size
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had been raised. Corrected.<br>
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A mixup of read buffers in the inet driver could cause unpredictable
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results when communicating over TCP and for distributed erlang.<br>
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(Own Id: OTP-4626)<br>
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Ets tables could show negative sizes in ets:info after a combination of
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safe_fixtable,delete and insert. The bug is removed.<br>
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(Own Id: OTP-4690)<br>
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process_info(Pid, garbage_collection) didn't return information about
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Pid; instead, it returned information about the calling process. This
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bug has now been corrected.<br>
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Repeated process_flag(Pid, save_calls, X) calls could cause
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erlang:memory() (and other memory information bifs) to return erroneous
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information. This bug has now been corrected.<br>
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(Own Id: OTP-4731)<br>
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ets:memory on set datatype could show wrong result after multiple
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inserts with same key. The error occurs after applying patch erl_487.
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The error is now corrected.<br>
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(Own Id: OTP-4756)<br>
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(Aux Id: OTP-4690, seq8001)<p>
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<!--- ----------------------------------------------------------------- --->
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<h3>Improvements and new features</h3>
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Support for the HW watchdog on the CP_blade board (PPC_LINUX)<br>
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(Own Id: OTP-4520)<p>
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Support for zombies has been removed. <code>erlang:system_flag/2</code>
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will no longer accept the <code>keep_zombies</code> argument.
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<code>process_info/2</code> will no longer accept the <code>exit</code>
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option (which was used to retrieve the exit reason for a zombie
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(*** POTENTIAL INCOMPATIBILITY ***)<br>
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(Own Id: OTP-4523)<p>
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The BIF erlang:hibernate/3 allows a process to shrink its memory
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consumption while waiting for messages.<br>
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(Own Id: OTP-4727)<p>
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A number of new memory allocators have been introduced in order to
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further reduce the memory consumption of the emulator. In order to
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resemble the Erlang/OTP R9B system, most of these allocators are
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disabled by default in the Erlang/OTP R9C release. By starting the
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emulator with the command-line argument "<code>+Mea r10b</code>", the
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emulator will use the default configuration we currently expect the
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Erlang/OTP R10B emulator to use. See the <code>erts_alloc(3)</code>
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documentation for further information. <br><br> Also new functionality for
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inspection of memory usage has been introduced. See the
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<code>instrument(3)</code>, <code>erlang:system_info/1</code>, and
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<code>erts_alloc(3)</code> documentation for further information. <br><br>
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<em>NOTE:</em> Some system flags (+ command line arguments passed to
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erl) have been changed. The <code>+m</code>, <code>+t</code>, and
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<code>+T</code> flags have been changed to, respectively,
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<code>+MYm</code>, <code>+MYtt</code>, and <code>+MYtp</code>. The
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<code>+d</code>, and <code>+S*</code> flags have been removed. See the
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<code>erts_alloc(3)</code>, and the <code>erl(1)</code> documentation
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for further information.<br>
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(*** POTENTIAL INCOMPATIBILITY ***)<br>
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(Own Id: OTP-4534)<br>
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(Aux Id: OTP-4761)<p>
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A way to make ets:update_counter wrap at certain values is now
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available. See the documentation for details.<br>
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(Own Id: OTP-4546)<br>
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(Aux Id: seq4605 (body9066))<p>
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The maximum number of ports can now be changed to an arbitrary value
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using the environment variable ERL_MAX_PORTS on windows, corresponding
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to the behaviour on other operating systems. The maximum number of
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simultaneously open i.e. sockets or port programs is now only limited
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by operating system imposed limits.<br>
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(Own Id: OTP-4578)<p>
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The beam files contain information about the source filenames unless
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(*** POTENTIAL INCOMPATIBILITY ***)<br>
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(Own Id: OTP-4611)<br>
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A method of getting notifications of long garbage collections, large
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heaps and suspended processes due to busy ports is now available. See
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the documentation of erlang:system_monitor/0..2.<br>
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(Own Id: OTP-4627)<br>
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erlang:memory/0 and erlang:memory/1 have been added.
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erlang:memory/[0,1] return the same type of information as
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c:memory/[0,1] previously did. The erlang:memory/[0,1] functions
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operate in constant time. c:memory/[0,1] now use erlang:memory/[0,1]
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and do therefore now also operate in constant time (which they
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previously did not). <br> erlang:memory/[0,1] return more accurate
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information than c:memory/[0,1] previously did. <br> For more
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information about erlang:memory/[0,1] see the erlang(3) man page.<br>
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(Own Id: OTP-4637)<p>
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A new class of error messages "warnings" are added. Warnings can be
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mapped to either error reports (the default), Info reports or a new
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class of reports, namely "warning reports". Non severe errors in OTP
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will be reported as warnings instead of forcing error reports.<br>
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(Own Id: OTP-4638)<br>
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The <code>gen_tcp:shutdown/2</code> function has been added. To handle
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shutdown from the other side, the option <code>{exit_on_close,
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true|false}</code> has been added to the <code>inet:setops/2</code>
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(Own Id: OTP-4664)<p>
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To give applications better control of conversion of local time to UTC
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with respect to daylight saving time, there are two new functions:
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erlang:localtime_to_universaltime/2 and
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calendar:local_time_to_uinversal_time_dst/1. See the documentation for
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(Own Id: OTP-4667)<br>
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In order to conform to the Erlang specification, comparison between two
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pids was changed in the R9B release. This change did however break a
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deadlock- prevention algorithm used by mnesia during release upgrade.
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Therefore, comparison between two pids has been changed back so that
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R9B nodes are compatible with Erlang nodes running pre-R9 releases.
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<br> Pre-R9 comparison between two pids which now is used again: If t1
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and t2 are both pids, t1 will precede t2 if and only if either * the
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node local id of t1 precedes the node local id of t2, or * the node
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local ids of t1 and t2 are equal, and node(t1) precedes node(t2), or *
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the node local ids of t1 and t2 are equal, and also node(t1) and
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node(t2) are equal, and node(t1) was created before node(t2). <br> The
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node local id consist of two integers; serial which is most
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significant, and number. <br> The Erlang specification states: If t1
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and t2 are both refs, both PIDs, or both ports, then t1 precedes t2 if
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and only if either * node(t1) precedes node(t2), or * node(t1) equals
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node(t2) and t1 was created before t2. <br> Note that comparisons
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between two refs, or two ports will still conform to the Erlang
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(*** POTENTIAL INCOMPATIBILITY ***)<br>
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(Own Id: OTP-4715)<br>
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(Aux Id: OTP-4511, OTP-4512)<p>
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The <code>erlang:fun_info/2</code> function will now return the name of
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the local function that implements the fun. Also, the
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<code>arity</code> information returned has now been documented.<br>
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(Own Id: OTP-4719)<br>
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(Aux Id: OTP-4704)<p>
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<p>A http state bug in inet_drv (affecting gen_tcp) has been fixed.
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Patch from Claes Wikstr�m. <p>A bug in defining max number of ports has
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been fixed. Patch from Claes Wikstr�m. <p>A bug in erlang:port_call/3
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when calling a driver with a NULL driver struct ->call field has been
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fixed. Patch from Luke Gorrie. <p>There is a new function
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file:script/1,2 that does the same as file:eval/1 but gives a return
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value. For completness, file:path_script/2,3, file:eval/2 and
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file:path_eval/3 are also added. Suggestion from Ulf Wiger. See the
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documentation for details. <p><code>erlang:trace/3</code> did no clear
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trace flags on processes that were exiting. This bug has now been
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fixed. <p>The gen_udp options <code>add_membership</code> and
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<code>drop_membership</code> are now allowed. Patch from Vance Shipley.
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<p><code>gen_udp:open/1,2</code> with service name instead of port
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number now works. Patch from carlos@lfcia.org. <p>An unjustified
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compiler warning when using an explicit space character as pad
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character to <code>io:format/2</code> and similar has been removed.
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<p>If an illegal node name is used to start a node, now
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<code>net_kernel</code> fails noisily instead of just letting the node
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start in non-distributed mode. <p>Now
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<code>gen_server:format_status/2</code> also works with non-registered
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processes. <p>There are two new functions
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<code>erlang:list_to_integer/2</code> and
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<code>erlang:integer_to_list/2</code> that takes a number base
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argument. See the documentataion for details. <p>New format characters
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for <code>io:format/2</code> and similar are ~b, ~B, ~x, ~X, ~+ and ~#.
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See the documentaion for details. <p>New format characters for
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<code>io:fread/2</code> and similar are ~u, ~- and ~#. See the
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documentation for details. <p>The token scanner <code>erl_scan</code>
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has been rewritten to become twice as fast as before. Now, incomplete
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any-base numbers such as "16#" are regarded as errors instead of as
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zero. The allowed base number range has been extended to 2..36 instead
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of previously 2..16. <p>There is a new function
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<code>lists:split/2</code>. See the documentation. <p>For everyone that
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has written their own function to calculate the time difference between
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two <code>now()</code> calls there is now
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<code>timer:now_diff/2</code>. See the documentation.<br>
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(Own Id: OTP-4747)<p>
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<!--- ################################################################# --->
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<!--- ----------------------------------------------------------------- --->
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<h3>Fixed errors and malfunctions</h3>
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Bit syntax matching in the shell used to allow expressions for sizes;
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this is now disallowed just as it is in compiled code.<br>
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(Own Id: OTP-3781)<br>
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(Aux Id: Seq 5004)<p>
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spawn_opt/4 used 0 as default value for fullsweep_after instead of the
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default value used by spawn/3, and spawn_link/3. This caused all
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processes spawned by spawn_opt/4 (e.g. all gen_servers) to allways use
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fullsweep if the fullsweep_after option wasn't explicitly set.
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spawn_opt/4 has now been changed to use the same default value as
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spawn/3, and spawn_link/3.<br>
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(*** POTENTIAL INCOMPATIBILITY ***)<br>
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(Own Id: OTP-4179)<p>
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The spawn bifs didn't fail with badarg as they should if the argument
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list wasn't a list; instead, the spawned process immediately exited.
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All spawn BIFs now fail with badarg if they are passed a bad argument
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as argument list. <br> spawn BIFs which take funs as arguments and
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remote spawn BIFs could fail with other errors than badarg when passed
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bad arguments. All spawn BIFs now fail with badarg when they fail due
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to bad arguments.<br>
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(Own Id: OTP-4185)<p>
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Negative field sizes in construction of binaries using the bit syntax
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would crash the emulator. Corrected.<br>
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(Own Id: OTP-4301)<p>
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System flags (+ command line arguments) taking values weren't handled
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correctly. If the value and the system flag were separated by
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whitespace some flags didn't work (e.g. +A 10). If multiple system
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flags with their corresponding values were passed, and the flags and
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the values were separated by whitespace, all of these flags were
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replaced by the last one passed. These bugs have now been corrected.<br>
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(Own Id: OTP-4312)<br>
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(Aux Id: OTP-4267, OTP-4313, OTP-4314)<p>
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The emulator could deadlock on vfork() due to operations performed in
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the child process before exec() (only observed on multi-processor
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machines). This bug has now been fixed.<br>
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(Own Id: OTP-4389)<br>
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When running the instrumented emulator and sl_alloc release 1,
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sl_realloc could fail to preserve all information. This has now been
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(Own Id: OTP-4419)<br>
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(Aux Id: OTP-4570)<p>
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Harmless bug (which caused compilation warnings on some platforms)
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fixed in sl_alloc (release 2)<br>
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(Own Id: OTP-4420)<p>
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Documentation of obsolete system flag +s removed<br>
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(Own Id: OTP-4421)<p>
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A bug in <code>file</code> that failed to flush write buffers after
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write errors, for example device full, and caused subsequent writes
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(after repositioning to a still writable position in the file) to write
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invalid data, has been corrected.<br>
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(Own Id: OTP-4505)<br>
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(Aux Id: OTP-4500)<p>
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<p>A bug that causes <code>inet_drv.c</code> not to free prebound
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sockets has been corrected. <p>A bug that caused
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<code>prim_inet:getiflist/1</code> to miss some interfaces has been
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(Own Id: OTP-4508)<p>
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A bug in the emulator that caused a memory leak if there had been more
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than 1024 ports open, and a port driver called <code>driver_exit</code>
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(A link from process to port was lost), has been corrected.<br>
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(Own Id: OTP-4509)<p>
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A bug that caused a segfault in the emulator when decoding a bad
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distribution message has been corrected.<br>
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(Own Id: OTP-4510)<p>
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<!--- ----------------------------------------------------------------- --->
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<h3>Improvements and new features</h3>
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The previous hard system limit of 255 known remote nodes has been
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removed. With the exception of node name atoms, all data regarding
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remote nodes are now garbage collected.<br>
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(Own Id: OTP-4196)<p>
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sl_alloc release 2 has been introduced in the emulator, see the
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sl_alloc(3) man page for more information.<br>
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(Own Id: OTP-4267)<br>
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(Aux Id: seq7276, OTP-4312, OTP-4313, OTP-4314)<p>
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The format of the monitor messages has been changed. The
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<code>Object</code> field in the <code>{'DOWN', MonitorReference, Type,
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Object, Info}</code> messages is now always on the form
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<code>{RegisteredName, NodeName}</code> when
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<code>erlang:monitor/2</code> has been called with a registered name
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(*** POTENTIAL INCOMPATIBILITY ***)<br>
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(Own Id: OTP-4311)<br>
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More memory block types (most of the existing ones) are now identified
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by the instrumented emulator.<br>
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(Own Id: OTP-4313)<br>
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(Aux Id: OTP-4267, OTP-4312, OTP-4314)<p>
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Memory blocks in the emulator that are guaranteed never to be removed
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are placed in a special block at the beginning of the emulators heap
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segment if there are space left in it. This special block has been
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called the definite alloc block. The size of the definite alloc block
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can be set with the +d system flag (see the erl(1) manpage) (default
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size is 2 Mb). <br> The tuple {definite_alloc, BlockSize, UsedSize}
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that is part of the list returned from
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erlang:system_info(allocated_areas) can be used to determine how much
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that is used of the definite alloc block.<br>
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(Own Id: OTP-4314)<br>
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(Aux Id: seq7276, OTP-4267, OTP-4312, OTP-4313)<p>
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A number of sl_alloc improvements have been made. For example, the
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block header field have been shrunk, and some useless features have
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(Own Id: OTP-4343)<br>
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(Aux Id: OTP-4267)<p>
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There are now two new trace breakpoint types - meta trace and call
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count trace. See erlang:trace_pattern/3 and erlang:trace_info/2.<br>
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(Own Id: OTP-4397)<p>
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The possibility to use elib_malloc instead of the default (libc) malloc
496
has been added. The +m command line switch is used in order to enable
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another malloc than the default (see the erl(1) man page). In order to
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enable elib_malloc use "+m elib".<br>
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(Own Id: OTP-4398)<br>
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There is a new portable hash function, <code>erlang:phash2</code>, that
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distributes small integers better than <code>erlang:phash</code>, and
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is faster for bignums and binaries.<br>
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(Own Id: OTP-4399)<p>
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The endianess specification 'native' has been added to the bit syntax.
512
It will resolve to either big or little endian at load time. It is
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specially useful for communcating with linked-in drivers.<br>
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(Own Id: OTP-4458)<p>
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The control() routine in a driver called for a port that is set in
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binary mode (using set_port_control_flags()), is now allowed to return
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a NULL pointer instead of a pointer to a binary. A NULL pointer will be
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returned to the caller of port_control/3 as an empty list.<br>
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(Own Id: OTP-4459)<p>
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<p> Comparisons between two <code>port</code>s or between two
527
<code>reference</code>s were previously unstable and didn't conform to
528
the Erlang specification. Comparisons between two <code>pid</code>s
529
didn't previously conform to the Erlang specification. The comparison
530
between two <code>pid</code>s, <code>port</code>s, or
531
<code>reference</code>s has therefore been changed and is now stable,
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and does now conform to the Erlang specification. </p> <p> Cut from the
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Erlang specification:<br> If <code>t1</code> and <code>t2</code> are
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both refs, both PIDs, or both ports, then <code>t1</code> precedes
535
<code>t2</code> if and only if either<br> * <code>node(t1)</code>
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precedes <code>node(t2)</code>, or<br> * <code>node(t1)</code> equals
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<code>node(t2)</code> and <code>t1</code> was created before
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<code>t2</code>. </p><br>
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(*** POTENTIAL INCOMPATIBILITY ***)<br>
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(Own Id: OTP-4511)<p>
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There are also release notes for
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<a href="notes_history.html">older versions</a>.
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