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-rw-r--r--lib/stdlib/doc/src/gen_fsm.xml16
-rw-r--r--lib/stdlib/doc/src/gen_server.xml3
-rw-r--r--lib/stdlib/doc/src/gen_statem.xml187
-rw-r--r--system/doc/design_principles/des_princ.xml6
-rw-r--r--system/doc/design_principles/fsm.xml12
-rw-r--r--system/doc/design_principles/release_handling.xml4
-rw-r--r--system/doc/design_principles/statem.xml9
-rw-r--r--system/doc/design_principles/sup_princ.xml2
8 files changed, 164 insertions, 75 deletions
diff --git a/lib/stdlib/doc/src/gen_fsm.xml b/lib/stdlib/doc/src/gen_fsm.xml
index 4d594b8eb2..835e252704 100644
--- a/lib/stdlib/doc/src/gen_fsm.xml
+++ b/lib/stdlib/doc/src/gen_fsm.xml
@@ -4,7 +4,7 @@
<erlref>
<header>
<copyright>
- <year>1996</year><year>2014</year>
+ <year>1996</year><year>2016</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -31,12 +31,23 @@
<module>gen_fsm</module>
<modulesummary>Generic Finite State Machine Behaviour</modulesummary>
<description>
+ <note>
+ <p>
+ There is a new behaviour
+ <seealso marker="gen_statem"><c>gen_statem</c></seealso>
+ that is intended to replace <c>gen_fsm</c> for new code.
+ It has the same features and add some really useful.
+ This module will not be removed for the foreseeable future
+ to keep old state machine implementations running.
+ </p>
+ </note>
<p>A behaviour module for implementing a finite state machine.
A generic finite state machine process (gen_fsm) implemented
using this module will have a standard set of interface functions
and include functionality for tracing and error reporting. It will
also fit into an OTP supervision tree. Refer to
- <seealso marker="doc/design_principles:fsm">OTP Design Principles</seealso> for more information.</p>
+ <seealso marker="doc/design_principles:fsm">OTP Design Principles</seealso> for more information.
+ </p>
<p>A gen_fsm assumes all specific parts to be located in a callback
module exporting a pre-defined set of functions. The relationship
between the behaviour functions and the callback functions can be
@@ -848,6 +859,7 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
<title>SEE ALSO</title>
<p><seealso marker="gen_event">gen_event(3)</seealso>,
<seealso marker="gen_server">gen_server(3)</seealso>,
+ <seealso marker="gen_statem">gen_statem(3)</seealso>,
<seealso marker="supervisor">supervisor(3)</seealso>,
<seealso marker="proc_lib">proc_lib(3)</seealso>,
<seealso marker="sys">sys(3)</seealso></p>
diff --git a/lib/stdlib/doc/src/gen_server.xml b/lib/stdlib/doc/src/gen_server.xml
index 6d04771cd4..10dc978afc 100644
--- a/lib/stdlib/doc/src/gen_server.xml
+++ b/lib/stdlib/doc/src/gen_server.xml
@@ -4,7 +4,7 @@
<erlref>
<header>
<copyright>
- <year>1996</year><year>2014</year>
+ <year>1996</year><year>2016</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -715,6 +715,7 @@ gen_server:abcast -----> Module:handle_cast/2
<title>SEE ALSO</title>
<p><seealso marker="gen_event">gen_event(3)</seealso>,
<seealso marker="gen_fsm">gen_fsm(3)</seealso>,
+ <seealso marker="gen_statem">gen_statem(3)</seealso>,
<seealso marker="supervisor">supervisor(3)</seealso>,
<seealso marker="proc_lib">proc_lib(3)</seealso>,
<seealso marker="sys">sys(3)</seealso></p>
diff --git a/lib/stdlib/doc/src/gen_statem.xml b/lib/stdlib/doc/src/gen_statem.xml
index adca3673be..91332fbdde 100644
--- a/lib/stdlib/doc/src/gen_statem.xml
+++ b/lib/stdlib/doc/src/gen_statem.xml
@@ -34,12 +34,40 @@
<p>
A behaviour module for implementing a state machine. Two
<seealso marker="#type-callback_mode"><em>callback modes</em></seealso>
- are supported. One for a finite state
- machine like <seealso marker="gen_fsm">gen_fsm</seealso>
- that requires the state to be an atom and use that state as
- the name of the callback function for a particular state,
+ are supported. One for finite state machines
+ (<seealso marker="gen_fsm"><c>gen_fsm</c></seealso> like)
+ that requires the state to be an atom and uses that state as
+ the name of the current callback function,
and one without restriction on the state data type
- that uses the same callback function for all states.
+ that uses one callback function for all states.
+ </p>
+ <p>
+ This is a new behaviour in OTP-19.0.
+ It has been thoroughly reviewed, is stable enough
+ to be used by at least two heavy OTP applications, and is here to stay.
+ But depending on user feedback, we do not expect
+ but might find it necessary to make minor
+ not backwards compatible changes into OTP-20.0,
+ so its state can be designated as "not quite experimental"...
+ </p>
+ <p>
+ The <c>gen_statem</c> behaviour is intended to replace
+ <seealso marker="gen_fsm"><c>gen_fsm</c></seealso> for new code.
+ It has the same features and add some really useful:
+ </p>
+ <list type="bulleted">
+ <item>State code is gathered</item>
+ <item>The state can be any term</item>
+ <item>Events can be postponed</item>
+ <item>Events can be self generated</item>
+ <item>A reply can be sent from a later state</item>
+ <item>There can be multiple sys traceable replies</item>
+ </list>
+ <p>
+ The callback model(s) for <c>gen_statem</c> differs from
+ the one for <seealso marker="gen_fsm"><c>gen_fsm</c></seealso>,
+ but it is still fairly easy to rewrite
+ from <c>gen_fsm</c> to <c>gen_statem</c>.
</p>
<p>
A generic state machine process (<c>gen_statem</c>) implemented
@@ -148,15 +176,15 @@ erlang:'!' -----> Module:StateName/3
to the state function. That is: as if it is
the oldest incoming event. There is a dedicated
<seealso marker="#type-event_type">
- <c>event_type()</c> <c>internal</c>
+ <c>event_type()</c>
</seealso>
- that can be used for such events making them impossible
+ <c>internal</c> that can be used for such events making them impossible
to mistake for external events.
</p>
<p>
Inserting an event replaces the trick of calling your own
state handling functions that you often would have to
- resort to in for example <seealso marker="gen_fsm">gen_fsm</seealso>
+ resort to in for example <seealso marker="gen_fsm"><c>gen_fsm</c></seealso>
to force processing an inserted event before others.
A warning, though: if you in <c>gen_statem</c> for example
postpone an event in one state and then call some other state function of yours,
@@ -172,9 +200,8 @@ erlang:'!' -----> Module:StateName/3
</p>
<p>
A <c>gen_statem</c> handles system messages as documented in
- <seealso marker="sys">sys</seealso>.
- The <seealso marker="sys">sys</seealso> module
- can be used for debugging a <c>gen_statem</c>.
+ <seealso marker="sys"><c>sys</c></seealso>.
+ The <c>sys</c>module can be used for debugging a <c>gen_statem</c>.
</p>
<p>
Note that a <c>gen_statem</c> does not trap exit signals
@@ -354,7 +381,7 @@ handle_event(_, _, State, Data) ->
<p>
Server specification to use when addressing
a <c>gen_statem</c> server.
- See <seealso marker="#call/2">call/2</seealso> and
+ See <seealso marker="#call/2"><c>call/2</c></seealso> and
<seealso marker="#type-server_name">
<c>server_name()</c>
</seealso>
@@ -397,7 +424,7 @@ handle_event(_, _, State, Data) ->
<p>
Debug option that can be used when starting
a <c>gen_statem</c> server through for example
- <seealso marker="#enter_loop/5">enter_loop/5</seealso>.
+ <seealso marker="#enter_loop/5"><c>enter_loop/5</c></seealso>.
</p>
<p>
For every entry in <c><anno>Dbgs</anno></c>
@@ -412,7 +439,7 @@ handle_event(_, _, State, Data) ->
<p>
Options that can be used when starting
a <c>gen_statem</c> server through for example
- <seealso marker="#start_link/3">start_link/3</seealso>.
+ <seealso marker="#start_link/3"><c>start_link/3</c></seealso>.
</p>
</desc>
</datatype>
@@ -421,7 +448,7 @@ handle_event(_, _, State, Data) ->
<desc>
<p>
Return value from the start functions for_example
- <seealso marker="#start_link/3">start_link/3</seealso>.
+ <seealso marker="#start_link/3"><c>start_link/3</c></seealso>.
</p>
</desc>
</datatype>
@@ -432,10 +459,11 @@ handle_event(_, _, State, Data) ->
<p>
Destination to use when replying through for example the
<seealso marker="#type-action">
- action() {reply,From,Reply}
+ <c>action()</c>
</seealso>
+ <c>{reply,From,Reply}</c>
to a process that has called the <c>gen_statem</c> server using
- <seealso marker="#call/2">call/2</seealso>.
+ <seealso marker="#call/2"><c>call/2</c></seealso>.
</p>
</desc>
</datatype>
@@ -465,7 +493,7 @@ handle_event(_, _, State, Data) ->
<p>
A term in which the state machine implementation
should store any server data it needs. The difference between
- this and the <seealso marker="#type-state">state()</seealso>
+ this and the <seealso marker="#type-state"><c>state()</c></seealso>
itself is that a change in this data does not cause
postponed events to be retried. Hence if a change
in this data would change the set of events that
@@ -498,9 +526,13 @@ handle_event(_, _, State, Data) ->
<p>
The <em>callback mode</em> is selected when starting the
<c>gen_statem</c> using the return value from
- <seealso marker="#Module:init/1">Module:init/1</seealso>
+ <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso>
or when calling
- <seealso marker="#enter_loop/5">enter_loop/5-7</seealso>.
+ <seealso marker="#enter_loop/5"><c>enter_loop/5-7</c></seealso>,
+ and with the return value from
+ <seealso marker="#Module:code_change/4">
+ <c>Module:code_change/4</c>.
+ </seealso>
</p>
<taglist>
<tag><c>state_functions</c></tag>
@@ -536,7 +568,7 @@ handle_event(_, _, State, Data) ->
<list type="ordered">
<item>
All
- <seealso marker="#type-action"><c>actions</c></seealso>
+ <seealso marker="#type-action">actions</seealso>
are processed in order of appearance.
</item>
<item>
@@ -554,20 +586,22 @@ handle_event(_, _, State, Data) ->
<item>
All events stored with
<seealso marker="#type-action">
- <c>action() next_event</c>
+ <c>action()</c>
</seealso>
+ <c>next_event</c>
are inserted in the queue to be processed before
all other events.
</item>
<item>
If an
<seealso marker="#type-event_timeout">
- <em><c>event_timeout()</c></em>
+ <c>event_timeout()</c>
</seealso>
is set through
<seealso marker="#type-action">
- <c>action() timeout</c>
+ <c>action()</c>
</seealso>
+ <c>timeout</c>
an event timer may be started or a timeout zero event
may be enqueued.
</item>
@@ -622,7 +656,8 @@ handle_event(_, _, State, Data) ->
<desc>
<p>
Generate an event of
- <seealso marker="#type-event_type">type <c>timeout</c></seealso>
+ <seealso marker="#type-event_type"><c>event_type()</c></seealso>
+ <c>timeout</c>
after this time (in milliseconds) unless some other
event arrives in which case this timeout is cancelled.
Note that a retried or inserted event
@@ -652,9 +687,9 @@ handle_event(_, _, State, Data) ->
These state transition actions may be invoked by
returning them from the
<seealso marker="#state_function">state function</seealso>,
- from <seealso marker="#Module:init/1">Module:init/1</seealso>
+ from <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso>
or by giving them to
- <seealso marker="#enter_loop/6">enter_loop/6,7</seealso>.
+ <seealso marker="#enter_loop/6"><c>enter_loop/6,7</c></seealso>.
</p>
<p>
Actions are executed in the containing list order.
@@ -677,20 +712,26 @@ handle_event(_, _, State, Data) ->
<item>
Set the
<seealso marker="#type-transition_option">
- <c>transition_option() postpone()</c>
+ <c>transition_option()</c>
+ </seealso>
+ <seealso marker="#type-postpone">
+ <c>postpone()</c>
</seealso>
for this state transition.
This action is ignored when returned from
- <seealso marker="#Module:init/1">Module:init/1</seealso>
+ <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso>
or given to
- <seealso marker="#enter_loop/5">enter_loop/5,6</seealso>
+ <seealso marker="#enter_loop/5"><c>enter_loop/5,6</c></seealso>
since there is no event to postpone in those cases.
</item>
<tag><c>hibernate</c></tag>
<item>
Set the
<seealso marker="#type-transition_option">
- <c>transition_option() hibernate()</c>
+ <c>transition_option()</c>
+ </seealso>
+ <seealso marker="#type-hibernate">
+ <c>hibernate()</c>
</seealso>
for this state transition.
</item>
@@ -703,13 +744,17 @@ handle_event(_, _, State, Data) ->
return value <c>{next_state,NextState,NewData,Timeout}</c>
allowed like for
<seealso marker="gen_fsm#Module:StateName/2">
- gen_fsm Module:StateName/2</seealso>.
+ <c>gen_fsm Module:StateName/2</c>.
+ </seealso>
</item>
<tag><c>timeout</c></tag>
<item>
Set the
<seealso marker="#type-transition_option">
- <c>transition_option() event_timeout()</c>
+ <c>transition_option()</c>
+ </seealso>
+ <seealso marker="#type-event_timeout">
+ <c>event_timeout()</c>
</seealso>
to <c><anno>Time</anno></c> with <c><anno>EventContent</anno></c>.
</item>
@@ -906,7 +951,7 @@ handle_event(_, _, State, Data) ->
If the option <c>{spawn_opt,SpawnOpts}</c> is present in
<c><anno>Opts</anno></c>, <c>SpawnOpts</c> will be passed
as option list to
- <seealso marker="erts:erlang#spawn_opt/2">spawn_opt/2</seealso>
+ <seealso marker="erts:erlang#spawn_opt/2"><c>spawn_opt/2</c></seealso>
which is used to spawn the <c>gen_statem</c> process.
</p>
<note>
@@ -967,7 +1012,7 @@ handle_event(_, _, State, Data) ->
to start a child.
</p>
<p>
- See <seealso marker="#start_link/3">start_link/3,4</seealso>
+ See <seealso marker="#start_link/3"><c>start_link/3,4</c></seealso>
for a description of arguments and return values.
</p>
</desc>
@@ -979,7 +1024,9 @@ handle_event(_, _, State, Data) ->
<desc>
<p>
The same as
- <seealso marker="#stop/3"><c>stop(<anno>ServerRef</anno>, normal, infinity)</c></seealso>.
+ <seealso marker="#stop/3">
+ <c>stop(<anno>ServerRef</anno>, normal, infinity)</c>.
+ </seealso>
</p>
</desc>
</func>
@@ -996,7 +1043,7 @@ handle_event(_, _, State, Data) ->
and waits for it to terminate.
The <c>gen_statem</c> will call
<seealso marker="#Module:terminate/3">
- Module:terminate/3
+ <c>Module:terminate/3</c>
</seealso>
before exiting.
</p>
@@ -1005,7 +1052,9 @@ handle_event(_, _, State, Data) ->
with the expected reason. Any other reason than <c>normal</c>,
<c>shutdown</c>, or <c>{shutdown,Term}</c> will cause an
error report to be issued through
- <seealso marker="kernel:error_logger#format/2">error_logger:format/2</seealso>.
+ <seealso marker="kernel:error_logger#format/2">
+ <c>error_logger:format/2</c>.
+ </seealso>
The default <c><anno>Reason</anno></c> is <c>normal</c>.
</p>
<p>
@@ -1125,7 +1174,7 @@ handle_event(_, _, State, Data) ->
<note>
<p>
A reply sent with this function will not be visible
- in <seealso marker="sys">sys</seealso> debug output.
+ in <seealso marker="sys"><c>sys</c></seealso> debug output.
</p>
</note>
</desc>
@@ -1194,7 +1243,9 @@ handle_event(_, _, State, Data) ->
<c><anno>Module</anno></c>, <c><anno>Opts</anno></c> and
<c><anno>Server</anno></c> have the same meanings
as when calling
- <seealso marker="#start_link/3"><c>gen_statem</c>:start[_link]/3,4</seealso>.
+ <seealso marker="#start_link/3">
+ <c>gen_statem:start[_link]/3,4</c>.
+ </seealso>
However, the
<seealso marker="#type-server_name">
<c>server_name()</c>
@@ -1205,7 +1256,7 @@ handle_event(_, _, State, Data) ->
<c><anno>CallbackMode</anno></c>, <c><anno>State</anno></c>,
<c><anno>Data</anno></c> and <c><anno>Actions</anno></c>
have the same meanings as in the return value of
- <seealso marker="#Module:init/1">Module:init/1</seealso>.
+ <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso>.
Also, the callback module <c><anno>Module</anno></c>
does not need to export an <c>init/1</c> function.
</p>
@@ -1259,9 +1310,9 @@ handle_event(_, _, State, Data) ->
<marker id="Module:init-1" />
<p>
Whenever a <c>gen_statem</c> is started using
- <seealso marker="#start_link/3">start_link/3,4</seealso>
+ <seealso marker="#start_link/3"><c>start_link/3,4</c></seealso>
or
- <seealso marker="#start/3">start/3,4</seealso>,
+ <seealso marker="#start/3"><c>start/3,4</c></seealso>,
this function is called by the new process to initialize
the implementation state and server data.
</p>
@@ -1277,9 +1328,9 @@ handle_event(_, _, State, Data) ->
<seealso marker="#type-callback_mode"><em>callback mode</em></seealso>.
of the <c>gen_statem</c>.
<c>State</c> is the initial
- <seealso marker="#type-state">state()</seealso>
+ <seealso marker="#type-state"><c>state()</c></seealso>
and <c>Data</c> the initial server
- <seealso marker="#type-data">data()</seealso>.
+ <seealso marker="#type-data"><c>data()</c></seealso>.
</p>
<p>
The <seealso marker="#type-action"><c>Actions</c></seealso>
@@ -1291,11 +1342,11 @@ handle_event(_, _, State, Data) ->
If something goes wrong during the initialization
the function should return <c>{stop,Reason}</c>
or <c>ignore</c>. See
- <seealso marker="#start_link/3">start_link/3,4</seealso>.
+ <seealso marker="#start_link/3"><c>start_link/3,4</c></seealso>.
</p>
<p>
This function may use
- <seealso marker="erts:erlang#throw/1"><c>throw</c></seealso>
+ <seealso marker="erts:erlang#throw/1"><c>throw/1</c></seealso>
to return <c>Result</c>.
</p>
</desc>
@@ -1339,8 +1390,8 @@ handle_event(_, _, State, Data) ->
<desc>
<p>
Whenever a <c>gen_statem</c> receives an event from
- <seealso marker="#call/2">call/2</seealso>,
- <seealso marker="#cast/2">cast/2</seealso> or
+ <seealso marker="#call/2"><c>call/2</c></seealso>,
+ <seealso marker="#cast/2"><c>cast/2</c></seealso> or
as a normal process message one of these functions is called. If
<seealso marker="#type-callback_mode"><em>callback mode</em></seealso>
is <c>state_functions</c> then <c>Module:StateName/3</c> is called,
@@ -1354,8 +1405,8 @@ handle_event(_, _, State, Data) ->
from this or from any other
<seealso marker="#state_function">state function</seealso>
by returning with <c>{reply,From,Reply}</c> in
- <seealso marker="#type-action">Actions</seealso>, in
- <seealso marker="#type-reply_action">Replies</seealso>
+ <seealso marker="#type-action"><c>Actions</c></seealso>, in
+ <seealso marker="#type-reply_action"><c>Replies</c></seealso>
or by calling
<seealso marker="#reply/2"><c>reply(From, Reply)</c></seealso>.
</p>
@@ -1371,13 +1422,13 @@ handle_event(_, _, State, Data) ->
there is no restriction on the next state.
</p>
<p>
- See <seealso marker="#type-action">action()</seealso>
+ See <seealso marker="#type-action"><c>action()</c></seealso>
for options that can be set and actions that can be done
by <c>gen_statem</c> after returning from this function.
</p>
<p>
These functions may use
- <seealso marker="erts:erlang#throw/1"><c>throw</c></seealso>,
+ <seealso marker="erts:erlang#throw/1"><c>throw/1</c></seealso>,
to return the result.
</p>
</desc>
@@ -1402,7 +1453,7 @@ handle_event(_, _, State, Data) ->
value is ignored.</p>
<p>
<c>Reason</c> is a term denoting the stop reason and
- <seealso marker="#type-state">State</seealso>
+ <seealso marker="#type-state"><c>State</c></seealso>
is the internal state of the <c>gen_statem</c>.
</p>
<p>
@@ -1410,7 +1461,7 @@ handle_event(_, _, State, Data) ->
is terminating.
If it is because another callback function has returned a
stop tuple <c>{stop,Reason}</c> in
- <seealso marker="#type-action">Actions</seealso>,
+ <seealso marker="#type-action"><c>Actions</c></seealso>,
<c>Reason</c> will have the value specified in that tuple.
If it is due to a failure, <c>Reason</c> is the error reason.
</p>
@@ -1445,11 +1496,13 @@ handle_event(_, _, State, Data) ->
<c>shutdown</c>, or <c>{shutdown,Term}</c>
the <c>gen_statem</c> is assumed to terminate due to an error
and an error report is issued using
- <seealso marker="kernel:error_logger#format/2">error_logger:format/2</seealso>.
+ <seealso marker="kernel:error_logger#format/2">
+ <c>error_logger:format/2</c>.
+ </seealso>
</p>
<p>
This function may use
- <seealso marker="erts:erlang#throw/1"><c>throw</c></seealso>
+ <seealso marker="erts:erlang#throw/1"><c>throw/1</c></seealso>
to return <c>Ignored</c>, which is ignored anyway.
</p>
</desc>
@@ -1504,7 +1557,9 @@ handle_event(_, _, State, Data) ->
<note>
<p>
If you would dare to change
- <seealso marker="#type-callback_mode"><em>callback mode</em></seealso>
+ <seealso marker="#type-callback_mode">
+ <em>callback mode</em>
+ </seealso>
during release upgrade/downgrade, the upgrade is no problem
since the new code surely knows what <em>callback mode</em>
it needs, but for a downgrade this function will have to
@@ -1534,7 +1589,7 @@ handle_event(_, _, State, Data) ->
upgrade will fail and roll back to the old release.</p>
<p>
This function may use
- <seealso marker="erts:erlang#throw/1"><c>throw</c></seealso>
+ <seealso marker="erts:erlang#throw/1"><c>throw/1</c></seealso>
to return <c>Result</c> or <c>Reason</c>.
</p>
</desc>
@@ -1640,7 +1695,7 @@ handle_event(_, _, State, Data) ->
</p>
<p>
This function may use
- <seealso marker="erts:erlang#throw/1"><c>throw</c></seealso>
+ <seealso marker="erts:erlang#throw/1"><c>throw/1</c></seealso>
to return <c>Status</c>.
</p>
</desc>
@@ -1650,11 +1705,11 @@ handle_event(_, _, State, Data) ->
<section>
<title>SEE ALSO</title>
- <p><seealso marker="gen_event">gen_event</seealso>,
- <seealso marker="gen_fsm">gen_fsm</seealso>,
- <seealso marker="gen_server">gen_server</seealso>,
- <seealso marker="supervisor">supervisor</seealso>,
- <seealso marker="proc_lib">proc_lib</seealso>,
- <seealso marker="sys">sys</seealso></p>
+ <p><seealso marker="gen_event"><c>gen_event(3)</c></seealso>,
+ <seealso marker="gen_fsm"><c>gen_fsm(3)</c></seealso>,
+ <seealso marker="gen_server"><c>gen_server(3)</c></seealso>,
+ <seealso marker="supervisor"><c>supervisor(3)</c></seealso>,
+ <seealso marker="proc_lib"><c>proc_lib(3)</c></seealso>,
+ <seealso marker="sys"><c>sys(3)</c></seealso></p>
</section>
</erlref>
diff --git a/system/doc/design_principles/des_princ.xml b/system/doc/design_principles/des_princ.xml
index 0e087cf843..8ab8661c2d 100644
--- a/system/doc/design_principles/des_princ.xml
+++ b/system/doc/design_principles/des_princ.xml
@@ -4,7 +4,7 @@
<chapter>
<header>
<copyright>
- <year>1997</year><year>2013</year>
+ <year>1997</year><year>2016</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -226,7 +226,9 @@ free(Ch, {Alloc, Free} = Channels) ->
<item><p><seealso marker="gen_server_concepts">gen_server</seealso></p>
<p>For implementing the server of a client-server relation</p></item>
<item><p><seealso marker="fsm">gen_fsm</seealso></p>
- <p>For implementing finite-state machines</p></item>
+ <p>For implementing finite-state machines (Old)</p></item>
+ <item><p><seealso marker="statem">gen_statem</seealso></p>
+ <p>For implementing state machines (New)</p></item>
<item><p><seealso marker="events">gen_event</seealso></p>
<p>For implementing event handling functionality</p></item>
<item><p><seealso marker="sup_princ">supervisor</seealso></p>
diff --git a/system/doc/design_principles/fsm.xml b/system/doc/design_principles/fsm.xml
index f58b50cbff..3468f93ae0 100644
--- a/system/doc/design_principles/fsm.xml
+++ b/system/doc/design_principles/fsm.xml
@@ -4,7 +4,7 @@
<chapter>
<header>
<copyright>
- <year>1997</year><year>2013</year>
+ <year>1997</year><year>2016</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -30,6 +30,16 @@
<file>fsm.xml</file>
</header>
<marker id="gen_fsm behaviour"></marker>
+ <note>
+ <p>
+ There is a new behaviour
+ <seealso marker="gen_statem"><c>gen_statem</c></seealso>
+ that is intended to replace <c>gen_fsm</c> for new code.
+ It has the same features and add some really useful.
+ This module will not be removed for the foreseeable future
+ to keep old state machine implementations running.
+ </p>
+ </note>
<p>This section is to be read with the <c>gen_fsm(3)</c> manual page
in STDLIB, where all interface functions and callback
functions are described in detail.</p>
diff --git a/system/doc/design_principles/release_handling.xml b/system/doc/design_principles/release_handling.xml
index 20ddc3dbf5..4f71ad4437 100644
--- a/system/doc/design_principles/release_handling.xml
+++ b/system/doc/design_principles/release_handling.xml
@@ -4,7 +4,7 @@
<chapter>
<header>
<copyright>
- <year>2003</year><year>2014</year>
+ <year>2003</year><year>2016</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -249,7 +249,7 @@
<p>If <c>Modules=dynamic</c>, which is the case for event
managers, the event manager process informs the release handler
about the list of currently installed event handlers
- (<c>gen_fsm</c>), and it is checked if the module name is in
+ (<c>gen_event</c>), and it is checked if the module name is in
this list instead.</p>
<p>The release handler suspends, asks for code change, and
resumes processes by calling the functions
diff --git a/system/doc/design_principles/statem.xml b/system/doc/design_principles/statem.xml
index 27b9b7c761..a921a40243 100644
--- a/system/doc/design_principles/statem.xml
+++ b/system/doc/design_principles/statem.xml
@@ -36,6 +36,15 @@
manual page in STDLIB, where all interface functions and callback
functions are described in detail.
</p>
+ <p>
+ This is a new behaviour in OTP-19.0.
+ It has been thoroughly reviewed, is stable enough
+ to be used by at least two heavy OTP applications, and is here to stay.
+ But depending on user feedback, we do not expect
+ but might find it necessary to make minor
+ not backwards compatible changes into OTP-20.0,
+ so its state can be designated as "not quite experimental"...
+ </p>
<!-- =================================================================== -->
diff --git a/system/doc/design_principles/sup_princ.xml b/system/doc/design_principles/sup_princ.xml
index a6b7dbb68d..749c9f69f2 100644
--- a/system/doc/design_principles/sup_princ.xml
+++ b/system/doc/design_principles/sup_princ.xml
@@ -402,8 +402,8 @@ supervisor:delete_child(Sup, Id)</code>
restarts.</p>
</section>
- <marker id="simple"/>
<section>
+ <marker id="simple"/>
<title>Simplified one_for_one Supervisors</title>
<p>A supervisor with restart strategy <c>simple_one_for_one</c> is
a simplified <c>one_for_one</c> supervisor, where all child
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 18:18:28 +0000