aboutsummaryrefslogtreecommitdiffstats
path: root/lib
diff options
context:
space:
mode:
Diffstat (limited to 'lib')
-rw-r--r--lib/stdlib/doc/src/gen_fsm.xml1109
-rw-r--r--lib/stdlib/doc/src/gen_server.xml1
-rw-r--r--lib/stdlib/doc/src/gen_statem.xml11
-rw-r--r--lib/stdlib/doc/src/proc_lib.xml2
-rw-r--r--lib/stdlib/doc/src/supervisor.xml6
-rw-r--r--lib/stdlib/doc/src/sys.xml28
-rw-r--r--lib/stdlib/src/gen_fsm.erl20
-rw-r--r--lib/stdlib/src/otp_internal.erl49
8 files changed, 252 insertions, 974 deletions
diff --git a/lib/stdlib/doc/src/gen_fsm.xml b/lib/stdlib/doc/src/gen_fsm.xml
index 691a039e34..e70f347479 100644
--- a/lib/stdlib/doc/src/gen_fsm.xml
+++ b/lib/stdlib/doc/src/gen_fsm.xml
@@ -4,14 +4,14 @@
<erlref>
<header>
<copyright>
- <year>1996</year><year>2016</year>
+ <year>1996-2017</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
-
+
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
@@ -29,945 +29,176 @@
<rev></rev>
</header>
<module>gen_fsm</module>
- <modulesummary>Generic finite state machine behavior.</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.
- <c>gen_fsm</c> will not be removed for the foreseeable future
- to keep old state machine implementations running.
- </p>
- </note>
- <p>This behavior module provides a finite state machine.
- A generic finite state machine process (<c>gen_fsm</c>) implemented
- using this module has a standard set of interface functions
- and includes functionality for tracing and error reporting. It
- also fits into an OTP supervision tree. For more information, see
- <seealso marker="doc/design_principles:fsm">OTP Design Principles</seealso>.
- </p>
-
- <p>A <c>gen_fsm</c> process assumes all specific parts to be located in a
- callback module exporting a predefined set of functions. The relationship
- between the behavior functions and the callback functions is as
- follows:</p>
-
- <pre>
-gen_fsm module Callback module
--------------- ---------------
-gen_fsm:start
-gen_fsm:start_link -----> Module:init/1
-
-gen_fsm:stop -----> Module:terminate/3
-
-gen_fsm:send_event -----> Module:StateName/2
-
-gen_fsm:send_all_state_event -----> Module:handle_event/3
-
-gen_fsm:sync_send_event -----> Module:StateName/3
-
-gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
-
-- -----> Module:handle_info/3
-
-- -----> Module:terminate/3
+ <modulesummary>Deprecated and replaced by <seealso marker="gen_statem"><c>gen_statem</c></seealso> </modulesummary>
-- -----> Module:code_change/4</pre>
-
- <p>If a callback function fails or returns a bad value, the <c>gen_fsm</c>
- process terminates.</p>
-
- <p>A <c>gen_fsm</c> process handles system messages as described in
- <seealso marker="sys"><c>sys(3)</c></seealso>. The <c>sys</c> module
- can be used for debugging a <c>gen_fsm</c> process.</p>
-
- <p>Notice that a <c>gen_fsm</c> process does not trap exit signals
- automatically, this must be explicitly initiated in the callback
- module.</p>
-
- <p>Unless otherwise stated, all functions in this module fail if
- the specified <c>gen_fsm</c> process does not exist or if bad arguments
- are specified.</p>
-
- <p>The <c>gen_fsm</c> process can go into hibernation
- (see <seealso marker="erts:erlang#hibernate/3">
- <c>erlang:hibernate/3</c></seealso>) if a callback function
- specifies <c>'hibernate'</c> instead of a time-out value. This
- can be useful if the server is expected to be idle for a long
- time. However, use this feature with care, as hibernation
- implies at least two garbage collections (when hibernating and
- shortly after waking up) and is not something you want to do
- between each call to a busy state machine.</p>
+ <description>
+ <p> Deprecated and replaced by <seealso marker="gen_statem"><c>gen_statem</c></seealso> </p>
</description>
-
- <funcs>
- <func>
- <name>cancel_timer(Ref) -> RemainingTime | false</name>
- <fsummary>Cancel an internal timer in a generic FSM.</fsummary>
- <type>
- <v>Ref = reference()</v>
- <v>RemainingTime = integer()</v>
- </type>
- <desc>
- <p>Cancels an internal timer referred by <c>Ref</c> in the
- <c>gen_fsm</c> process that calls this function.</p>
- <p><c>Ref</c> is a reference returned from
- <seealso marker="#send_event_after/2">
- <c>send_event_after/2</c></seealso> or
- <seealso marker="#start_timer/2"><c>start_timer/2</c></seealso>.</p>
- <p>If the timer has already timed out, but the event not yet
- been delivered, it is cancelled as if it had <em>not</em>
- timed out, so there is no false timer event after
- returning from this function.</p>
- <p>Returns the remaining time in milliseconds until the timer would
- have expired if <c>Ref</c> referred to an active timer, otherwise
- <c>false</c>.</p>
- </desc>
- </func>
-
- <func>
- <name>enter_loop(Module, Options, StateName, StateData)</name>
- <name>enter_loop(Module, Options, StateName, StateData, FsmName)</name>
- <name>enter_loop(Module, Options, StateName, StateData, Timeout)</name>
- <name>enter_loop(Module, Options, StateName, StateData, FsmName, Timeout)</name>
- <fsummary>Enter the <c>gen_fsm</c> receive loop.</fsummary>
- <type>
- <v>Module = atom()</v>
- <v>Options = [Option]</v>
- <v>&nbsp;Option = {debug,Dbgs}</v>
- <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
- <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics</v>
- <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
- <v>StateName = atom()</v>
- <v>StateData = term()</v>
- <v>FsmName = {local,Name} | {global,GlobalName}</v>
- <v>&nbsp;&nbsp;| {via,Module,ViaName}</v>
- <v>&nbsp;Name = atom()</v>
- <v>&nbsp;GlobalName = ViaName = term()</v>
- <v>Timeout = int() | infinity</v>
- </type>
- <desc>
- <p>Makes an existing process into a <c>gen_fsm</c> process.
- Does not return,
- instead the calling process enters the <c>gen_fsm</c> receive
- loop and becomes a <c>gen_fsm</c> process. The process <em>must</em>
- have been started using one of the start functions in
- <seealso marker="proc_lib"><c>proc_lib(3)</c></seealso>. The user is
- responsible for any initialization of the process, including
- registering a name for it.</p>
- <p>This function is useful when a more complex initialization
- procedure is needed than the <c>gen_fsm</c> behavior provides.</p>
- <p><c>Module</c>, <c>Options</c>, and <c>FsmName</c> have
- the same meanings as when calling
- <seealso marker="#start_link/3"><c>start[_link]/3,4</c></seealso>.
- However, if <c>FsmName</c> is specified, the process must have
- been registered accordingly <em>before</em> this function is
- called.</p>
- <p><c>StateName</c>, <c>StateData</c>, and <c>Timeout</c> have
- the same meanings as in the return value of
- <seealso marker="#Moduleinit"><c>Module:init/1</c></seealso>.
- The callback module <c>Module</c> does not need to
- export an <c>init/1</c> function.</p>
- <p>The function fails if the calling process was not started by a
- <c>proc_lib</c> start function, or if it is not registered
- according to <c>FsmName</c>.</p>
- </desc>
- </func>
-
- <func>
- <name>reply(Caller, Reply) -> Result</name>
- <fsummary>Send a reply to a caller.</fsummary>
- <type>
- <v>Caller - see below</v>
- <v>Reply = term()</v>
- <v>Result = term()</v>
- </type>
- <desc>
- <p>This function can be used by a <c>gen_fsm</c> process to
- explicitly send a reply to a client process that called
- <seealso marker="#sync_send_event/2">
- <c>sync_send_event/2,3</c></seealso> or
- <seealso marker="#sync_send_all_state_event/2">
- <c>sync_send_all_state_event/2,3</c></seealso>
- when the reply cannot be defined in the return value of
- <seealso marker="#Module:StateName/3">
- <c>Module:StateName/3</c></seealso> or
- <seealso marker="#Module:handle_sync_event/4">
- <c>Module:handle_sync_event/4</c></seealso>.</p>
- <p><c>Caller</c> must be the <c>From</c> argument provided to
- the callback function. <c>Reply</c> is any term
- given back to the client as the return value of
- <c>sync_send_event/2,3</c> or
- <c>sync_send_all_state_event/2,3</c>.</p>
- <p>Return value <c>Result</c> is not further defined, and
- is always to be ignored.</p>
- </desc>
- </func>
-
- <func>
- <name>send_all_state_event(FsmRef, Event) -> ok</name>
- <fsummary>Send an event asynchronously to a generic FSM.</fsummary>
- <type>
- <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
- <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
- <v>&nbsp;Name = Node = atom()</v>
- <v>&nbsp;GlobalName = ViaName = term()</v>
- <v>Event = term()</v>
- </type>
- <desc>
- <p>Sends an event asynchronously to the <c>FsmRef</c> of the
- <c>gen_fsm</c> process and returns <c>ok</c> immediately.
- The <c>gen_fsm</c> process calls
- <seealso marker="#Module:handle_event/3">
- <c>Module:handle_event/3</c></seealso> to handle the event.</p>
- <p>For a description of the arguments, see
- <seealso marker="#send_event/2"><c>send_event/2</c></seealso>.</p>
- <p>The difference between <c>send_event/2</c> and
- <c>send_all_state_event/2</c> is which callback function is
- used to handle the event. This function is useful when
- sending events that are handled the same way in every state,
- as only one <c>handle_event</c> clause is needed to handle
- the event instead of one clause in each state name function.</p>
- </desc>
- </func>
-
- <func>
- <name>send_event(FsmRef, Event) -> ok</name>
- <fsummary>Send an event asynchronously to a generic FSM.</fsummary>
- <type>
- <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
- <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
- <v>&nbsp;Name = Node = atom()</v>
- <v>&nbsp;GlobalName = ViaName = term()</v>
- <v>Event = term()</v>
- </type>
- <desc>
- <p>Sends an event asynchronously to the <c>FsmRef</c> of the
- <c>gen_fsm</c> process
- and returns <c>ok</c> immediately. The <c>gen_fsm</c> process calls
- <seealso marker="#Module:StateName/2">
- <c>Module:StateName/2</c></seealso> to handle the event, where
- <c>StateName</c> is the name of the current state of
- the <c>gen_fsm</c> process.</p>
- <p><c>FsmRef</c> can be any of the following:</p>
- <list type="bulleted">
- <item>The pid</item>
- <item><c>Name</c>, if the <c>gen_fsm</c> process is locally
- registered</item>
- <item><c>{Name,Node}</c>, if the <c>gen_fsm</c> process is locally
- registered at another node</item>
- <item><c>{global,GlobalName}</c>, if the <c>gen_fsm</c> process is
- globally registered</item>
- <item><c>{via,Module,ViaName}</c>, if the <c>gen_fsm</c> process is
- registered through an alternative process registry</item>
- </list>
- <p><c>Event</c> is any term that is passed as one of
- the arguments to <c>Module:StateName/2</c>.</p>
- </desc>
- </func>
-
- <func>
- <name>send_event_after(Time, Event) -> Ref</name>
- <fsummary>Send a delayed event internally in a generic FSM.</fsummary>
- <type>
- <v>Time = integer()</v>
- <v>Event = term()</v>
- <v>Ref = reference()</v>
- </type>
- <desc>
- <p>Sends a delayed event internally in the <c>gen_fsm</c> process
- that calls this function after <c>Time</c> milliseconds.
- Returns immediately a
- reference that can be used to cancel the delayed send using
- <seealso marker="#cancel_timer/1"><c>cancel_timer/1</c></seealso>.</p>
- <p>The <c>gen_fsm</c> process calls
- <seealso marker="#Module:StateName/2">
- <c>Module:StateName/2</c></seealso> to handle
- the event, where <c>StateName</c> is the name of the current
- state of the <c>gen_fsm</c> process at the time the delayed event is
- delivered.</p>
- <p><c>Event</c> is any term that is passed as one of
- the arguments to <c>Module:StateName/2</c>.</p>
- </desc>
- </func>
-
- <func>
- <name>start(Module, Args, Options) -> Result</name>
- <name>start(FsmName, Module, Args, Options) -> Result</name>
- <fsummary>Create a standalone <c>gen_fsm</c> process.</fsummary>
- <type>
- <v>FsmName = {local,Name} | {global,GlobalName}</v>
- <v>&nbsp;&nbsp;| {via,Module,ViaName}</v>
- <v>&nbsp;Name = atom()</v>
- <v>&nbsp;GlobalName = ViaName = term()</v>
- <v>Module = atom()</v>
- <v>Args = term()</v>
- <v>Options = [Option]</v>
- <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {spawn_opt,SOpts}</v>
- <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
- <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics</v>
- <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
- <v>&nbsp;&nbsp;SOpts = [term()]</v>
- <v>Result = {ok,Pid} | ignore | {error,Error}</v>
- <v>&nbsp;Pid = pid()</v>
- <v>&nbsp;Error = {already_started,Pid} | term()</v>
- </type>
- <desc>
- <p>Creates a standalone <c>gen_fsm</c> process, that is, a process that
- is not part of a supervision tree and thus has no supervisor.</p>
- <p>For a description of arguments and return values, see
- <seealso marker="#start_link/3"><c>start_link/3,4</c></seealso>.</p>
- </desc>
- </func>
-
- <func>
- <name>start_link(Module, Args, Options) -> Result</name>
- <name>start_link(FsmName, Module, Args, Options) -> Result</name>
- <fsummary>Create a <c>gen_fsm</c> process in a supervision tree.
- </fsummary>
- <type>
- <v>FsmName = {local,Name} | {global,GlobalName}</v>
- <v>&nbsp;&nbsp;| {via,Module,ViaName}</v>
- <v>&nbsp;Name = atom()</v>
- <v>&nbsp;GlobalName = ViaName = term()</v>
- <v>Module = atom()</v>
- <v>Args = term()</v>
- <v>Options = [Option]</v>
- <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {spawn_opt,SOpts}</v>
- <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
- <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics</v>
- <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
- <v>&nbsp;&nbsp;SOpts = [SOpt]</v>
- <v>&nbsp;&nbsp;&nbsp;SOpt - see erlang:spawn_opt/2,3,4,5</v>
- <v>Result = {ok,Pid} | ignore | {error,Error}</v>
- <v>&nbsp;Pid = pid()</v>
- <v>&nbsp;Error = {already_started,Pid} | term()</v>
- </type>
- <desc>
- <p>Creates a <c>gen_fsm</c> process as part of a supervision tree.
- The function is to be called, directly or indirectly, by
- the supervisor. For example, it ensures that
- the <c>gen_fsm</c> process is linked to the supervisor.</p>
- <p>The <c>gen_fsm</c> process calls
- <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso> to
- initialize. To ensure a synchronized startup procedure,
- <c>start_link/3,4</c> does not return until
- <c>Module:init/1</c> has returned.</p>
- <list type="bulleted">
- <item>
- <p>If <c>FsmName={local,Name}</c>, the <c>gen_fsm</c> process is
- registered locally as <c>Name</c> using <c>register/2</c>.</p>
- </item>
- <item>
- <p>If <c>FsmName={global,GlobalName}</c>, the <c>gen_fsm</c> process
- is registered globally as <c>GlobalName</c> using
- <seealso marker="kernel:global#register_name/2">
- <c>global:register_name/2</c></seealso>.</p>
- </item>
- <item>
- <p>If <c>FsmName={via,Module,ViaName}</c>, the <c>gen_fsm</c>
- process registers with the registry represented by <c>Module</c>.
- The <c>Module</c> callback is to export the functions
- <c>register_name/2</c>, <c>unregister_name/1</c>,
- <c>whereis_name/1</c>, and <c>send/2</c>, which are to behave
- like the corresponding functions in
- <seealso marker="kernel:global"><c>global</c></seealso>.
- Thus, <c>{via,global,GlobalName}</c> is a valid reference.</p>
- </item>
- </list>
- <p>If no name is provided, the <c>gen_fsm</c> process is not
- registered.</p>
- <p><c>Module</c> is the name of the callback module.</p>
- <p><c>Args</c> is any term that is passed as
- the argument to <c>Module:init/1</c>.</p>
- <p>If option <c>{timeout,Time}</c> is present, the <c>gen_fsm</c>
- process is allowed to spend <c>Time</c> milliseconds initializing
- or it terminates and the start function returns
- <c>{error,timeout}</c>.</p>
- <p>If option <c>{debug,Dbgs}</c> is present, the corresponding
- <c>sys</c> function is called for each item in <c>Dbgs</c>; see
- <seealso marker="sys"><c>sys(3)</c></seealso>.</p>
- <p>If option <c>{spawn_opt,SOpts}</c> is present, <c>SOpts</c> is
- passed as option list to the <c>spawn_opt</c> BIF that is used to
- spawn the <c>gen_fsm</c> process; see
- <seealso marker="erts:erlang#spawn_opt/2">
- <c>spawn_opt/2</c></seealso>.</p>
- <note>
- <p>Using spawn option <c>monitor</c> is not
- allowed, it causes the function to fail with reason
- <c>badarg</c>.</p>
- </note>
- <p>If the <c>gen_fsm</c> process is successfully created and
- initialized, the function returns <c>{ok,Pid}</c>, where <c>Pid</c>
- is the pid of the <c>gen_fsm</c> process. If a process with the
- specified <c>FsmName</c> exists already, the function returns
- <c>{error,{already_started,Pid}}</c>, where <c>Pid</c> is
- the pid of that process.</p>
- <p>If <c>Module:init/1</c> fails with <c>Reason</c>,
- the function returns <c>{error,Reason}</c>. If
- <c>Module:init/1</c> returns <c>{stop,Reason}</c> or
- <c>ignore</c>, the process is terminated and the function
- returns <c>{error,Reason}</c> or <c>ignore</c>, respectively.</p>
- </desc>
- </func>
-
- <func>
- <name>start_timer(Time, Msg) -> Ref</name>
- <fsummary>Send a time-out event internally in a generic FSM.</fsummary>
- <type>
- <v>Time = integer()</v>
- <v>Msg = term()</v>
- <v>Ref = reference()</v>
- </type>
- <desc>
- <p>Sends a time-out event internally in the <c>gen_fsm</c>
- process that calls this function after <c>Time</c> milliseconds.
- Returns immediately a
- reference that can be used to cancel the timer using
- <seealso marker="#cancel_timer/1"><c>cancel_timer/1</c></seealso>.</p>
- <p>The <c>gen_fsm</c> process calls
- <seealso marker="#Module:StateName/2">
- <c>Module:StateName/2</c></seealso> to handle
- the event, where <c>StateName</c> is the name of the current
- state of the <c>gen_fsm</c> process at the time the time-out
- message is delivered.</p>
- <p><c>Msg</c> is any term that is passed in the
- time-out message, <c>{timeout, Ref, Msg}</c>, as one of
- the arguments to <c>Module:StateName/2</c>.</p>
- </desc>
- </func>
-
- <func>
- <name>stop(FsmRef) -> ok</name>
- <name>stop(FsmRef, Reason, Timeout) -> ok</name>
- <fsummary>Synchronously stop a generic FSM.</fsummary>
- <type>
- <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
- <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
- <v>&nbsp;Node = atom()</v>
- <v>&nbsp;GlobalName = ViaName = term()</v>
- <v>Reason = term()</v>
- <v>Timeout = int()>0 | infinity</v>
- </type>
- <desc>
- <p>Orders a generic finite state machine to exit with the specified
- <c>Reason</c> and waits for it to terminate. The <c>gen_fsm</c>
- process calls <seealso marker="#Module:terminate/3">
- <c>Module:terminate/3</c></seealso> before exiting.</p>
- <p>The function returns <c>ok</c> if the generic finite state machine
- terminates with the expected reason. Any other reason than
- <c>normal</c>, <c>shutdown</c>, or <c>{shutdown,Term}</c> causes an
- error report to be issued using
- <seealso marker="kernel:error_logger#format/2">
- <c>error_logger:format/2</c></seealso>.
- The default <c>Reason</c> is <c>normal</c>.</p>
- <p><c>Timeout</c> is an integer greater than zero that
- specifies how many milliseconds to wait for the generic FSM
- to terminate, or the atom <c>infinity</c> to wait
- indefinitely. The default value is <c>infinity</c>. If the
- generic finite state machine has not terminated within the specified
- time, a <c>timeout</c> exception is raised.</p>
- <p>If the process does not exist, a <c>noproc</c> exception
- is raised.</p>
- </desc>
- </func>
-
- <func>
- <name>sync_send_all_state_event(FsmRef, Event) -> Reply</name>
- <name>sync_send_all_state_event(FsmRef, Event, Timeout) -> Reply</name>
- <fsummary>Send an event synchronously to a generic FSM.</fsummary>
- <type>
- <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
- <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
- <v>&nbsp;Name = Node = atom()</v>
- <v>&nbsp;GlobalName = ViaName = term()</v>
- <v>Event = term()</v>
- <v>Timeout = int()>0 | infinity</v>
- <v>Reply = term()</v>
- </type>
- <desc>
- <p>Sends an event to the <c>FsmRef</c> of the <c>gen_fsm</c>
- process and waits until a reply arrives or a time-out occurs.
- The <c>gen_fsm</c> process calls
- <seealso marker="#Module:handle_sync_event/4">
- <c>Module:handle_sync_event/4</c></seealso> to handle the event.</p>
- <p>For a description of <c>FsmRef</c> and <c>Event</c>, see
- <seealso marker="#send_event/2">send_event/2</seealso>.
- For a description of <c>Timeout</c> and <c>Reply</c>, see
- <seealso marker="#sync_send_event/3">
- <c>sync_send_event/3</c></seealso>.</p>
- <p>For a discussion about the difference between
- <c>sync_send_event</c> and <c>sync_send_all_state_event</c>, see
- <seealso marker="#send_all_state_event/2">
- <c>send_all_state_event/2</c></seealso>.</p>
- </desc>
- </func>
-
- <func>
- <name>sync_send_event(FsmRef, Event) -> Reply</name>
- <name>sync_send_event(FsmRef, Event, Timeout) -> Reply</name>
- <fsummary>Send an event synchronously to a generic FSM.</fsummary>
- <type>
- <v>FsmRef = Name | {Name,Node} | {global,GlobalName}</v>
- <v>&nbsp;&nbsp;| {via,Module,ViaName} | pid()</v>
- <v>&nbsp;Name = Node = atom()</v>
- <v>&nbsp;GlobalName = ViaName = term()</v>
- <v>Event = term()</v>
- <v>Timeout = int()>0 | infinity</v>
- <v>Reply = term()</v>
- </type>
- <desc>
- <p>Sends an event to the <c>FsmRef</c> of the <c>gen_fsm</c>
- process and waits until a reply arrives or a time-out occurs.
- <c>The gen_fsm</c> process calls
- <seealso marker="#Module:StateName/3">
- <c>Module:StateName/3</c></seealso> to handle the event, where
- <c>StateName</c> is the name of the current state of
- the <c>gen_fsm</c> process.</p>
- <p>For a description of <c>FsmRef</c> and <c>Event</c>, see
- <seealso marker="#send_event/2"><c>send_event/2</c></seealso>.</p>
- <p><c>Timeout</c> is an integer greater than zero that
- specifies how many milliseconds to wait for a reply, or
- the atom <c>infinity</c> to wait indefinitely. Defaults
- to 5000. If no reply is received within the specified time,
- the function call fails.</p>
- <p>Return value <c>Reply</c> is defined in the return value
- of <c>Module:StateName/3</c>.</p>
- </desc>
- </func>
- </funcs>
-
- <section>
- <title>Callback Functions</title>
- <p>The following functions are to be exported from a <c>gen_fsm</c>
- callback module.</p>
-
- <p><em>state name</em> denotes a state of the state machine.</p>
-
- <p><em>state data</em> denotes the internal state of the Erlang process
- that implements the state machine.</p>
- </section>
-
- <funcs>
- <func>
- <name>Module:code_change(OldVsn, StateName, StateData, Extra) -> {ok, NextStateName, NewStateData}</name>
- <fsummary>Update the internal state data during upgrade/downgrade.
- </fsummary>
- <type>
- <v>OldVsn = Vsn | {down, Vsn}</v>
- <v>&nbsp;&nbsp;Vsn = term()</v>
- <v>StateName = NextStateName = atom()</v>
- <v>StateData = NewStateData = term()</v>
- <v>Extra = term()</v>
- </type>
- <desc>
- <note>
- <p>This callback is optional, so callback modules need not export it.
- If a release upgrade/downgrade with <c>Change={advanced,Extra}</c>
- specified in the <c>appup</c> file is made when <c>code_change/4</c>
- isn't implemented the process will crash with an <c>undef</c> exit
- reason.</p>
- </note>
- <p>This function is called by a <c>gen_fsm</c> process when it is to
- update its internal state data during a release upgrade/downgrade,
- that is, when instruction <c>{update,Module,Change,...}</c>,
- where <c>Change={advanced,Extra}</c>, is given in
- the <c>appup</c> file; see section
- <seealso marker="doc/design_principles:release_handling#instr">
- Release Handling Instructions</seealso> in OTP Design Principles.</p>
- <p>For an upgrade, <c>OldVsn</c> is <c>Vsn</c>, and for a downgrade,
- <c>OldVsn</c> is <c>{down,Vsn}</c>. <c>Vsn</c> is defined by the
- <c>vsn</c> attribute(s) of the old version of the callback module
- <c>Module</c>. If no such attribute is defined, the version is
- the checksum of the Beam file.</p>
- <p><c>StateName</c> is the current state name and <c>StateData</c> the
- internal state data of the <c>gen_fsm</c> process.</p>
- <p><c>Extra</c> is passed "as is" from the <c>{advanced,Extra}</c>
- part of the update instruction.</p>
- <p>The function is to return the new current state name and
- updated internal data.</p>
- </desc>
- </func>
-
- <func>
- <name>Module:format_status(Opt, [PDict, StateData]) -> Status</name>
- <fsummary>Optional function for providing a term describing the
- current <c>gen_fsm</c> process status.</fsummary>
- <type>
- <v>Opt = normal | terminate</v>
- <v>PDict = [{Key, Value}]</v>
- <v>StateData = term()</v>
- <v>Status = term()</v>
- </type>
- <desc>
- <note>
- <p>This callback is optional, so callback modules need not
- export it. The <c>gen_fsm</c> module provides a default
- implementation of this function that returns the callback
- module state data.</p>
- </note>
- <p>This function is called by a <c>gen_fsm</c> process in the
- following situations:</p>
- <list type="bulleted">
- <item>One of <seealso marker="sys#get_status/1">
- <c>sys:get_status/1,2</c></seealso>
- is invoked to get the <c>gen_fsm</c> status. <c>Opt</c> is set to
- the atom <c>normal</c> for this case.</item>
- <item>The <c>gen_fsm</c> process terminates abnormally and logs an
- error. <c>Opt</c> is set to the atom <c>terminate</c> for
- this case.</item>
- </list>
- <p>This function is useful for changing the form and
- appearance of the <c>gen_fsm</c> status for these cases. A callback
- module wishing to change the <c>sys:get_status/1,2</c>
- return value as well as how its status appears in
- termination error logs, exports an instance
- of <c>format_status/2</c> that returns a term describing the
- current status of the <c>gen_fsm</c> process.</p>
- <p><c>PDict</c> is the current value of the process dictionary of the
- <c>gen_fsm</c> process.</p>
- <p><c>StateData</c> is the internal state data of the
- <c>gen_fsm</c> process.</p>
- <p>The function is to return <c>Status</c>, a term that
- change the details of the current state and status of
- the <c>gen_fsm</c> process. There are no restrictions on the
- form <c>Status</c> can take, but for
- the <c>sys:get_status/1,2</c> case (when <c>Opt</c>
- is <c>normal</c>), the recommended form for
- the <c>Status</c> value is <c>[{data, [{"StateData",
- Term}]}]</c>, where <c>Term</c> provides relevant details of
- the <c>gen_fsm</c> state data. Following this recommendation is not
- required, but it makes the callback module status
- consistent with the rest of the <c>sys:get_status/1,2</c>
- return value.</p>
- <p>One use for this function is to return compact alternative
- state data representations to avoid that large state terms
- are printed in log files.</p>
- </desc>
- </func>
-
- <func>
- <name>Module:handle_event(Event, StateName, StateData) -> Result</name>
- <fsummary>Handle an asynchronous event.</fsummary>
- <type>
- <v>Event = term()</v>
- <v>StateName = atom()</v>
- <v>StateData = term()</v>
- <v>Result = {next_state,NextStateName,NewStateData}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
- <v>&nbsp;&nbsp;| {stop,Reason,NewStateData}</v>
- <v>&nbsp;NextStateName = atom()</v>
- <v>&nbsp;NewStateData = term()</v>
- <v>&nbsp;Timeout = int()>0 | infinity</v>
- <v>&nbsp;Reason = term()</v>
- </type>
- <desc>
- <p>Whenever a <c>gen_fsm</c> process receives an event sent using
- <seealso marker="#send_all_state_event/2">
- <c>send_all_state_event/2</c></seealso>,
- this function is called to handle the event.</p>
- <p><c>StateName</c> is the current state name of the <c>gen_fsm</c>
- process.</p>
- <p>For a description of the other arguments and possible return values,
- see <seealso marker="#Module:StateName/2">
- <c>Module:StateName/2</c></seealso>.</p>
- </desc>
- </func>
-
- <func>
- <name>Module:handle_info(Info, StateName, StateData) -> Result</name>
- <fsummary>Handle an incoming message.</fsummary>
- <type>
- <v>Info = term()</v>
- <v>StateName = atom()</v>
- <v>StateData = term()</v>
- <v>Result = {next_state,NextStateName,NewStateData}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
- <v>&nbsp;&nbsp;| {stop,Reason,NewStateData}</v>
- <v>&nbsp;NextStateName = atom()</v>
- <v>&nbsp;NewStateData = term()</v>
- <v>&nbsp;Timeout = int()>0 | infinity</v>
- <v>&nbsp;Reason = normal | term()</v>
- </type>
- <desc>
- <note>
- <p>This callback is optional, so callback modules need not
- export it. The <c>gen_fsm</c> module provides a default
- implementation of this function that logs about the unexpected
- <c>Info</c> message, drops it and returns
- <c>{next_state, StateName, StateData}</c>.</p>
- </note>
- <p>This function is called by a <c>gen_fsm</c> process when it receives
- any other message than a synchronous or asynchronous event (or a
- system message).</p>
- <p><c>Info</c> is the received message.</p>
- <p>For a description of the other arguments and possible return values,
- see <seealso marker="#Module:StateName/2">
- <c>Module:StateName/2</c></seealso>.</p>
- </desc>
- </func>
-
- <func>
- <name>Module:handle_sync_event(Event, From, StateName, StateData) -> Result</name>
- <fsummary>Handle a synchronous event.</fsummary>
- <type>
- <v>Event = term()</v>
- <v>From = {pid(),Tag}</v>
- <v>StateName = atom()</v>
- <v>StateData = term()</v>
- <v>Result = {reply,Reply,NextStateName,NewStateData}</v>
- <v>&nbsp;&nbsp;| {reply,Reply,NextStateName,NewStateData,Timeout}</v>
- <v>&nbsp;&nbsp;| {reply,Reply,NextStateName,NewStateData,hibernate}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
- <v>&nbsp;&nbsp;| {stop,Reason,Reply,NewStateData} | {stop,Reason,NewStateData}</v>
- <v>&nbsp;Reply = term()</v>
- <v>&nbsp;NextStateName = atom()</v>
- <v>&nbsp;NewStateData = term()</v>
- <v>&nbsp;Timeout = int()>0 | infinity</v>
- <v>&nbsp;Reason = term()</v>
- </type>
- <desc>
- <p>Whenever a <c>gen_fsm</c> process receives an event sent using
- <seealso marker="#sync_send_all_state_event/2">
- <c>sync_send_all_state_event/2,3</c></seealso>,
- this function is called to handle the event.</p>
- <p><c>StateName</c> is the current state name of the <c>gen_fsm</c>
- process.</p>
- <p>For a description of the other arguments and possible return values,
- see <seealso marker="#Module:StateName/3">
- <c>Module:StateName/3</c></seealso>.</p>
- </desc>
- </func>
-
- <func>
- <name>Module:init(Args) -> Result</name>
- <fsummary>Initialize process and internal state name and state data.
- </fsummary>
- <type>
- <v>Args = term()</v>
- <v>Result = {ok,StateName,StateData} | {ok,StateName,StateData,Timeout}</v>
- <v>&nbsp;&nbsp;| {ok,StateName,StateData,hibernate}</v>
- <v>&nbsp;&nbsp;| {stop,Reason} | ignore</v>
- <v>&nbsp;StateName = atom()</v>
- <v>&nbsp;StateData = term()</v>
- <v>&nbsp;Timeout = int()>0 | infinity</v>
- <v>&nbsp;Reason = term()</v>
- </type>
- <desc>
- <marker id="Moduleinit"></marker>
- <p>Whenever a <c>gen_fsm</c> process is started using
- <seealso marker="#start/3"><c>start/3,4</c></seealso> or
- <seealso marker="#start_link/3"><c>start_link/3,4</c></seealso>,
- this function is called by the new process to initialize.</p>
- <p><c>Args</c> is the <c>Args</c> argument provided to the start
- function.</p>
- <p>If initialization is successful, the function is to return
- <c>{ok,StateName,StateData}</c>,
- <c>{ok,StateName,StateData,Timeout}</c>, or
- <c>{ok,StateName,StateData,hibernate}</c>, where <c>StateName</c>
- is the initial state name and <c>StateData</c> the initial
- state data of the <c>gen_fsm</c> process.</p>
- <p>If an integer time-out value is provided, a time-out occurs
- unless an event or a message is received within <c>Timeout</c>
- milliseconds. A time-out is represented by the atom
- <c>timeout</c> and is to be handled by the
- <seealso marker="#Module:StateName/2">
- <c>Module:StateName/2</c></seealso> callback functions. The atom
- <c>infinity</c> can be used to wait indefinitely, this is
- the default value.</p>
- <p>If <c>hibernate</c> is specified instead of a time-out value, the
- process goes into hibernation when waiting for the next message
- to arrive (by calling <seealso marker="proc_lib#hibernate/3">
- <c>proc_lib:hibernate/3</c></seealso>).</p>
- <p>If the initialization fails, the function returns
- <c>{stop,Reason}</c>, where <c>Reason</c> is any term,
- or <c>ignore</c>.</p>
- </desc>
- </func>
-
- <func>
- <name>Module:StateName(Event, StateData) -> Result</name>
- <fsummary>Handle an asynchronous event.</fsummary>
- <type>
- <v>Event = timeout | term()</v>
- <v>StateData = term()</v>
- <v>Result = {next_state,NextStateName,NewStateData} </v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
- <v>&nbsp;&nbsp;| {stop,Reason,NewStateData}</v>
- <v>&nbsp;NextStateName = atom()</v>
- <v>&nbsp;NewStateData = term()</v>
- <v>&nbsp;Timeout = int()>0 | infinity</v>
- <v>&nbsp;Reason = term()</v>
- </type>
- <desc>
- <p>There is to be one instance of this function for each
- possible state name. Whenever a <c>gen_fsm</c> process receives
- an event sent using
- <seealso marker="#send_event/2"><c>send_event/2</c></seealso>,
- the instance of this function with the same name as
- the current state name <c>StateName</c> is called to handle
- the event. It is also called if a time-out occurs.</p>
- <p><c>Event</c> is either the atom <c>timeout</c>, if a time-out
- has occurred, or the <c>Event</c> argument provided to
- <c>send_event/2</c>.</p>
- <p><c>StateData</c> is the state data of the <c>gen_fsm</c> process.</p>
- <p>If the function returns
- <c>{next_state,NextStateName,NewStateData}</c>,
- <c>{next_state,NextStateName,NewStateData,Timeout}</c>, or
- <c>{next_state,NextStateName,NewStateData,hibernate}</c>, the
- <c>gen_fsm</c> process continues executing with the current state
- name set to <c>NextStateName</c> and with the possibly
- updated state data <c>NewStateData</c>. For a description of
- <c>Timeout</c> and <c>hibernate</c>, see
- <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso>.</p>
- <p>If the function returns <c>{stop,Reason,NewStateData}</c>,
- the <c>gen_fsm</c> process calls
- <c>Module:terminate(Reason,StateName,NewStateData)</c> and
- terminates.</p>
- </desc>
- </func>
-
- <func>
- <name>Module:StateName(Event, From, StateData) -> Result</name>
- <fsummary>Handle a synchronous event.</fsummary>
- <type>
- <v>Event = term()</v>
- <v>From = {pid(),Tag}</v>
- <v>StateData = term()</v>
- <v>Result = {reply,Reply,NextStateName,NewStateData}</v>
- <v>&nbsp;&nbsp;| {reply,Reply,NextStateName,NewStateData,Timeout}</v>
- <v>&nbsp;&nbsp;| {reply,Reply,NextStateName,NewStateData,hibernate}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,Timeout}</v>
- <v>&nbsp;&nbsp;| {next_state,NextStateName,NewStateData,hibernate}</v>
- <v>&nbsp;&nbsp;| {stop,Reason,Reply,NewStateData} | {stop,Reason,NewStateData}</v>
- <v>&nbsp;Reply = term()</v>
- <v>&nbsp;NextStateName = atom()</v>
- <v>&nbsp;NewStateData = term()</v>
- <v>&nbsp;Timeout = int()>0 | infinity</v>
- <v>&nbsp;Reason = normal | term()</v>
- </type>
- <desc>
- <p>There is to be one instance of this function for each
- possible state name. Whenever a <c>gen_fsm</c> process receives an
- event sent using <seealso marker="#sync_send_event/2">
- <c>sync_send_event/2,3</c></seealso>,
- the instance of this function with the same name as
- the current state name <c>StateName</c> is called to handle
- the event.</p>
- <p><c>Event</c> is the <c>Event</c> argument provided to
- <c>sync_send_event/2,3</c>.</p>
- <p><c>From</c> is a tuple <c>{Pid,Tag}</c> where <c>Pid</c> is
- the pid of the process that called <c>sync_send_event/2,3</c>
- and <c>Tag</c> is a unique tag.</p>
- <p><c>StateData</c> is the state data of the <c>gen_fsm</c> process.</p>
- <list type="bulleted">
- <item>
- <p>If <c>{reply,Reply,NextStateName,NewStateData}</c>,
- <c>{reply,Reply,NextStateName,NewStateData,Timeout}</c>, or
- <c>{reply,Reply,NextStateName,NewStateData,hibernate}</c> is
- returned, <c>Reply</c> is given back to <c>From</c> as the return
- value of <c>sync_send_event/2,3</c>. The <c>gen_fsm</c> process
- then continues executing with the current state name set to
- <c>NextStateName</c> and with the possibly updated state data
- <c>NewStateData</c>. For a description of <c>Timeout</c> and
- <c>hibernate</c>, see
- <seealso marker="#Module:init/1">
- <c>Module:init/1</c></seealso>.</p>
- </item>
- <item>
- <p>If <c>{next_state,NextStateName,NewStateData}</c>,
- <c>{next_state,NextStateName,NewStateData,Timeout}</c>, or
- <c>{next_state,NextStateName,NewStateData,hibernate}</c> is
- returned, the <c>gen_fsm</c> process continues executing in
- <c>NextStateName</c> with <c>NewStateData</c>.
- Any reply to <c>From</c> must be specified explicitly using
- <seealso marker="#reply/2"><c>reply/2</c></seealso>.</p>
- </item>
- <item>
- <p>If the function returns
- <c>{stop,Reason,Reply,NewStateData}</c>, <c>Reply</c> is
- given back to <c>From</c>. If the function returns
- <c>{stop,Reason,NewStateData}</c>, any reply to <c>From</c>
- must be specified explicitly using <c>reply/2</c>.
- The <c>gen_fsm</c> process then calls
- <c>Module:terminate(Reason,StateName,NewStateData)</c> and
- terminates.</p>
- </item>
- </list>
- </desc>
- </func>
-
- <func>
- <name>Module:terminate(Reason, StateName, StateData)</name>
- <fsummary>Clean up before termination.</fsummary>
- <type>
- <v>Reason = normal | shutdown | {shutdown,term()} | term()</v>
- <v>StateName = atom()</v>
- <v>StateData = term()</v>
- </type>
- <desc>
- <note>
- <p>This callback is optional, so callback modules need not
- export it. The <c>gen_fsm</c> module provides a default
- implementation without cleanup.</p>
- </note>
- <p>This function is called by a <c>gen_fsm</c> process when it is about
- to terminate. It is to be the opposite of
- <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso>
- and do any necessary cleaning up. When it returns, the <c>gen_fsm</c>
- process terminates with <c>Reason</c>. The return value is ignored.
- </p>
- <p><c>Reason</c> is a term denoting the stop reason,
- <c>StateName</c> is the current state name, and
- <c>StateData</c> is the state data of the <c>gen_fsm</c> process.</p>
- <p><c>Reason</c> depends on why the <c>gen_fsm</c> process is
- terminating. If
- it is because another callback function has returned a stop
- tuple <c>{stop,..}</c>, <c>Reason</c> has the value
- specified in that tuple. If it is because of a failure,
- <c>Reason</c> is the error reason.</p>
- <p>If the <c>gen_fsm</c> process is part of a supervision tree and is
- ordered by its supervisor to terminate, this function is called
- with <c>Reason=shutdown</c> if the following conditions apply:</p>
- <list type="bulleted">
- <item>
- <p>The <c>gen_fsm</c> process has been set to trap exit signals.</p>
- </item>
- <item>
- <p>The shutdown strategy as defined in the child specification of
- the supervisor is an integer time-out value, not
- <c>brutal_kill</c>.</p>
- </item>
- </list>
- <p>Even if the <c>gen_fsm</c> process is <em>not</em> part of a
- supervision tree,
- this function is called if it receives an <c>'EXIT'</c>
- message from its parent. <c>Reason</c> is the same as in
- the <c>'EXIT'</c> message.</p>
- <p>Otherwise, the <c>gen_fsm</c> process terminates immediately.</p>
- <p>Notice that for any other reason than <c>normal</c>,
- <c>shutdown</c>, or <c>{shutdown,Term}</c> the <c>gen_fsm</c> process
- is assumed to terminate because of an error and an error report is
- issued using <seealso marker="kernel:error_logger#format/2">
- <c>error_logger:format/2</c></seealso>.</p>
- </desc>
- </func>
- </funcs>
-
<section>
- <title>See Also</title>
- <p><seealso marker="gen_event"><c>gen_event(3)</c></seealso>,
- <seealso marker="gen_server"><c>gen_server(3)</c></seealso>,
- <seealso marker="gen_statem"><c>gen_statem(3)</c></seealso>,
- <seealso marker="proc_lib"><c>proc_lib(3)</c></seealso>,
- <seealso marker="supervisor"><c>supervisor(3)</c></seealso>,
- <seealso marker="sys"><c>sys(3)</c></seealso></p>
+ <marker id="Migration to gen_statem"/>
+ <title>Migration to gen_statem</title>
+
+ <p>Here follows a simple example of turning a gen_fsm into
+ a <seealso marker="gen_statem"><c>gen_statem</c></seealso>. The example comes
+ from the previous Users Guide for <c>gen_fsm</c> </p>
+
+ <code type="erl">
+-module(code_lock).
+-define(NAME, code_lock).
+%-define(BEFORE_REWRITE, true).
+
+-ifdef(BEFORE_REWRITE).
+-behaviour(gen_fsm).
+-else.
+-behaviour(gen_statem).
+-endif.
+
+-export([start_link/1, button/1, stop/0]).
+
+-ifdef(BEFORE_REWRITE).
+-export([init/1, locked/2, open/2, handle_sync_event/4, handle_event/3,
+ handle_info/3, terminate/3, code_change/4]).
+-else.
+-export([init/1, callback_mode/0, locked/3, open/3, terminate/3, code_change/4]).
+%% Add callback__mode/0
+%% Change arity of the state functions
+%% Remove handle_info/3
+-endif.
+
+-ifdef(BEFORE_REWRITE).
+start_link(Code) ->
+ gen_fsm:start_link({local, ?NAME}, ?MODULE, Code, []).
+-else.
+start_link(Code) ->
+ gen_statem:start_link({local,?NAME}, ?MODULE, Code, []).
+-endif.
+
+-ifdef(BEFORE_REWRITE).
+button(Digit) ->
+ gen_fsm:send_event(?NAME, {button, Digit}).
+-else.
+button(Digit) ->
+ gen_statem:cast(?NAME, {button,Digit}).
+ %% send_event is asynchronous and becomes a cast
+-endif.
+
+-ifdef(BEFORE_REWRITE).
+stop() ->
+ gen_fsm:sync_send_all_state_event(?NAME, stop).
+-else.
+stop() ->
+ gen_statem:call(?NAME, stop).
+ %% sync_send is synchronous and becomes call
+ %% all_state is handled by callback code in gen_statem
+-endif.
+
+init(Code) ->
+ do_lock(),
+ Data = #{code => Code, remaining => Code},
+ {ok, locked, Data}.
+
+-ifdef(BEFORE_REWRITE).
+-else.
+callback_mode() ->
+ state_functions.
+%% state_functions mode is the mode most similar to
+%% gen_fsm. There is also handle_event mode which is
+%% a fairly different concept.
+-endif.
+
+-ifdef(BEFORE_REWRITE).
+locked({button, Digit}, Data0) ->
+ case analyze_lock(Digit, Data0) of
+ {open = StateName, Data} ->
+ {next_state, StateName, Data, 10000};
+ {StateName, Data} ->
+ {next_state, StateName, Data}
+ end.
+-else.
+locked(cast, {button,Digit}, Data0) ->
+ case analyze_lock(Digit, Data0) of
+ {open = StateName, Data} ->
+ {next_state, StateName, Data, 10000};
+ {StateName, Data} ->
+ {next_state, StateName, Data}
+ end;
+locked({call, From}, Msg, Data) ->
+ handle_call(From, Msg, Data);
+locked({info, Msg}, StateName, Data) ->
+ handle_info(Msg, StateName, Data).
+%% Arity differs
+%% All state events are dispatched to handle_call and handle_info help
+%% functions. If you want to handle a call or cast event specifically
+%% for this state you would add a special clause for it above.
+-endif.
+
+-ifdef(BEFORE_REWRITE).
+open(timeout, State) ->
+ do_lock(),
+ {next_state, locked, State};
+open({button,_}, Data) ->
+ {next_state, locked, Data}.
+-else.
+open(timeout, _, Data) ->
+ do_lock(),
+ {next_state, locked, Data};
+open(cast, {button,_}, Data) ->
+ {next_state, locked, Data};
+open({call, From}, Msg, Data) ->
+ handle_call(From, Msg, Data);
+open(info, Msg, Data) ->
+ handle_info(Msg, open, Data).
+%% Arity differs
+%% All state events are dispatched to handle_call and handle_info help
+%% functions. If you want to handle a call or cast event specifically
+%% for this state you would add a special clause for it above.
+-endif.
+
+-ifdef(BEFORE_REWRITE).
+handle_sync_event(stop, _From, _StateName, Data) ->
+ {stop, normal, ok, Data}.
+
+handle_event(Event, StateName, Data) ->
+ {stop, {shutdown, {unexpected, Event, StateName}}, Data}.
+
+handle_info(Info, StateName, Data) ->
+ {stop, {shutdown, {unexpected, Info, StateName}}, StateName, Data}.
+-else.
+-endif.
+
+terminate(_Reason, State, _Data) ->
+ State =/= locked andalso do_lock(),
+ ok.
+code_change(_Vsn, State, Data, _Extra) ->
+ {ok, State, Data}.
+
+%% Internal functions
+-ifdef(BEFORE_REWRITE).
+-else.
+handle_call(From, stop, Data) ->
+ {stop_and_reply, normal, {reply, From, ok}, Data}.
+
+handle_info(Info, StateName, Data) ->
+ {stop, {shutdown, {unexpected, Info, StateName}}, StateName, Data}.
+%% These are internal functions for handling all state events
+%% and not behaviour callbacks as in gen_fsm
+-endif.
+
+analyze_lock(Digit, #{code := Code, remaining := Remaining} = Data) ->
+ case Remaining of
+ [Digit] ->
+ do_unlock(),
+ {open, Data#{remaining := Code}};
+ [Digit|Rest] -> % Incomplete
+ {locked, Data#{remaining := Rest}};
+ _Wrong ->
+ {locked, Data#{remaining := Code}}
+ end.
+
+do_lock() ->
+ io:format("Lock~n", []).
+do_unlock() ->
+ io:format("Unlock~n", []).
+ </code>
</section>
</erlref>
diff --git a/lib/stdlib/doc/src/gen_server.xml b/lib/stdlib/doc/src/gen_server.xml
index 4540449792..0bcbbc2805 100644
--- a/lib/stdlib/doc/src/gen_server.xml
+++ b/lib/stdlib/doc/src/gen_server.xml
@@ -814,7 +814,6 @@ gen_server:abcast -----> Module:handle_cast/2
<section>
<title>See Also</title>
<p><seealso marker="gen_event"><c>gen_event(3)</c></seealso>,
- <seealso marker="gen_fsm"><c>gen_fsm(3)</c></seealso>,
<seealso marker="gen_statem"><c>gen_statem(3)</c></seealso>,
<seealso marker="proc_lib"><c>proc_lib(3)</c></seealso>,
<seealso marker="supervisor"><c>supervisor(3)</c></seealso>,
diff --git a/lib/stdlib/doc/src/gen_statem.xml b/lib/stdlib/doc/src/gen_statem.xml
index 5eb13db1aa..18089a8191 100644
--- a/lib/stdlib/doc/src/gen_statem.xml
+++ b/lib/stdlib/doc/src/gen_statem.xml
@@ -62,8 +62,8 @@
</p>
</note>
<p>
- The <c>gen_statem</c> behavior is intended to replace
- <seealso marker="gen_fsm"><c>gen_fsm</c></seealso> for new code.
+ The <c>gen_statem</c> behavior replaces
+ <seealso marker="gen_fsm"><c>gen_fsm</c> </seealso> in Erlang/OTP 20.0.
It has the same features and adds some really useful:
</p>
<list type="bulleted">
@@ -78,8 +78,10 @@
<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>.
+ but it is still fairly easy to
+ <seealso marker="gen_fsm#Migration to gen_statem">
+ rewrite from
+ </seealso> <c>gen_fsm</c> to <c>gen_statem</c>.
</p>
<p>
A generic state machine process (<c>gen_statem</c>) implemented
@@ -945,7 +947,6 @@ handle_event(_, _, State, Data) ->
<seealso marker="#state callback">state callback</seealso>
return value <c>{next_state,NextState,NewData,Timeout}</c>
allowed like for <c>gen_fsm</c>'s
- <seealso marker="gen_fsm#Module:StateName/2"><c>Module:StateName/2</c></seealso>.
</p>
</item>
<tag><c>timeout</c></tag>
diff --git a/lib/stdlib/doc/src/proc_lib.xml b/lib/stdlib/doc/src/proc_lib.xml
index e64b2ce18a..7939a0ef61 100644
--- a/lib/stdlib/doc/src/proc_lib.xml
+++ b/lib/stdlib/doc/src/proc_lib.xml
@@ -36,7 +36,7 @@
the <seealso marker="doc/design_principles:des_princ">
OTP Design Principles</seealso>. Specifically, the functions in this
module are used by the OTP standard behaviors (for example,
- <c>gen_server</c>, <c>gen_fsm</c>, and <c>gen_statem</c>)
+ <c>gen_server</c> and <c>gen_statem</c>)
when starting new processes. The functions
can also be used to start <em>special processes</em>, user-defined
processes that comply to the OTP design principles. For an example,
diff --git a/lib/stdlib/doc/src/supervisor.xml b/lib/stdlib/doc/src/supervisor.xml
index bb06d3645e..a42cfdd567 100644
--- a/lib/stdlib/doc/src/supervisor.xml
+++ b/lib/stdlib/doc/src/supervisor.xml
@@ -36,7 +36,6 @@
process can either be another supervisor or a worker process.
Worker processes are normally implemented using one of the
<seealso marker="gen_event"><c>gen_event</c></seealso>,
- <seealso marker="gen_fsm"><c>gen_fsm</c></seealso>,
<seealso marker="gen_server"><c>gen_server</c></seealso>, or
<seealso marker="gen_statem"><c>gen_statem</c></seealso>
behaviors. A supervisor implemented using this module has
@@ -237,8 +236,8 @@ child_spec() = #{id => child_id(), % mandatory
<p><c>modules</c> is used by the release handler during code
replacement to determine which processes are using a certain
module. As a rule of thumb, if the child process is a
- <c>supervisor</c>, <c>gen_server</c>,
- <c>gen_statem</c>, or <c>gen_fsm</c>,
+ <c>supervisor</c>, <c>gen_server</c> or,
+ <c>gen_statem</c>,
this is to be a list with one element <c>[Module]</c>,
where <c>Module</c> is the callback module. If the child
process is an event manager (<c>gen_event</c>) with a
@@ -706,7 +705,6 @@ child_spec() = #{id => child_id(), % mandatory
<section>
<title>See Also</title>
<p><seealso marker="gen_event"><c>gen_event(3)</c></seealso>,
- <seealso marker="gen_fsm"><c>gen_fsm(3)</c></seealso>,
<seealso marker="gen_statem"><c>gen_statem(3)</c></seealso>,
<seealso marker="gen_server"><c>gen_server(3)</c></seealso>,
<seealso marker="sys"><c>sys(3)</c></seealso></p>
diff --git a/lib/stdlib/doc/src/sys.xml b/lib/stdlib/doc/src/sys.xml
index 45171f814d..78840aaaf3 100644
--- a/lib/stdlib/doc/src/sys.xml
+++ b/lib/stdlib/doc/src/sys.xml
@@ -168,12 +168,6 @@
</item>
<item>
<p>For a
- <seealso marker="gen_fsm"><c>gen_fsm</c></seealso>
- process, <c><anno>State</anno></c> is the tuple
- <c>{CurrentStateName, CurrentStateData}</c>.</p>
- </item>
- <item>
- <p>For a
<seealso marker="gen_statem"><c>gen_statem</c></seealso>
process, <c><anno>State</anno></c> is the tuple
<c>{CurrentState,CurrentData}</c>.</p>
@@ -222,7 +216,7 @@
<p>Function <c>system_get_state/1</c> is primarily useful for
user-defined behaviors and modules that implement OTP
<seealso marker="#special_process">special processes</seealso>.
- The <c>gen_server</c>, <c>gen_fsm</c>,
+ The <c>gen_server</c>,
<c>gen_statem</c>, and <c>gen_event</c> OTP
behavior modules export this function, so callback modules for those
behaviors need not to supply their own.</p>
@@ -246,11 +240,6 @@
process returns the state of the callback module.</p>
</item>
<item>
- <p>A <seealso marker="gen_fsm"><c>gen_fsm</c></seealso>
- process returns information, such as its current
- state name and state data.</p>
- </item>
- <item>
<p>A <seealso marker="gen_statem"><c>gen_statem</c></seealso>
process returns information, such as its current
state name and state data.</p>
@@ -262,14 +251,12 @@
</item>
</list>
<p>Callback modules for <c>gen_server</c>,
- <c>gen_fsm</c>, <c>gen_statem</c>, and <c>gen_event</c>
+ <c>gen_statem</c>, and <c>gen_event</c>
can also change the value of <c><anno>Misc</anno></c>
by exporting a function <c>format_status/2</c>, which contributes
module-specific information. For details, see
<seealso marker="gen_server#Module:format_status/2">
<c>gen_server:format_status/2</c></seealso>,
- <seealso marker="gen_fsm#Module:format_status/2">
- <c>gen_fsm:format_status/2</c></seealso>,
<seealso marker="gen_statem#Module:format_status/2">
<c>gen_statem:format_status/2</c></seealso>, and
<seealso marker="gen_event#Module:format_status/2">
@@ -373,13 +360,6 @@
is a new instance of that state.</p>
</item>
<item>
- <p>For a <seealso marker="gen_fsm"><c>gen_fsm</c></seealso> process,
- <c><anno>State</anno></c> is the tuple <c>{CurrentStateName,
- CurrentStateData}</c>, and <c><anno>NewState</anno></c> is a
- similar tuple, which can contain
- a new state name, new state data, or both.</p>
- </item>
- <item>
<p>For a <seealso marker="gen_statem"><c>gen_statem</c></seealso>
process, <c><anno>State</anno></c> is the
tuple <c>{CurrentState,CurrentData}</c>,
@@ -422,7 +402,7 @@
return its <c><anno>State</anno></c> argument.</p>
<p>If a <c><anno>StateFun</anno></c> function crashes or throws an
exception, the original state of the process is unchanged for
- <c>gen_server</c>, <c>gen_fsm</c>, and <c>gen_statem</c> processes.
+ <c>gen_server</c>, and <c>gen_statem</c> processes.
For <c>gen_event</c> processes, a crashing or
failing <c><anno>StateFun</anno></c> function
means that only the state of the particular event handler it was
@@ -462,7 +442,7 @@
user-defined behaviors and modules that implement OTP
<seealso marker="#special_process">special processes</seealso>. The
OTP behavior modules <c>gen_server</c>,
- <c>gen_fsm</c>, <c>gen_statem</c>, and <c>gen_event</c>
+ <c>gen_statem</c>, and <c>gen_event</c>
export this function, so callback modules for those
behaviors need not to supply their own.</p>
</desc>
diff --git a/lib/stdlib/src/gen_fsm.erl b/lib/stdlib/src/gen_fsm.erl
index 39a8fd42fe..d413da3ea1 100644
--- a/lib/stdlib/src/gen_fsm.erl
+++ b/lib/stdlib/src/gen_fsm.erl
@@ -124,6 +124,26 @@
system_replace_state/2,
format_status/2]).
+-deprecated({start, 3, next_major_release}).
+-deprecated({start, 4, next_major_release}).
+-deprecated({start_link, 3, next_major_release}).
+-deprecated({start_link, 4, next_major_release}).
+-deprecated({stop, 1, next_major_release}).
+-deprecated({stop, 3, next_major_release}).
+-deprecated({send_event, 2, next_major_release}).
+-deprecated({sync_send_event, 2, next_major_release}).
+-deprecated({sync_send_event, 3, next_major_release}).
+-deprecated({send_all_state_event, 2, next_major_release}).
+-deprecated({sync_send_all_state_event, 2, next_major_release}).
+-deprecated({sync_send_all_state_event, 3, next_major_release}).
+-deprecated({reply, 2, next_major_release}).
+-deprecated({start_timer, 2, next_major_release}).
+-deprecated({send_event_after, 2, next_major_release}).
+-deprecated({cancel_timer, 1, next_major_release}).
+-deprecated({enter_loop, 4, next_major_release}).
+-deprecated({enter_loop, 5, next_major_release}).
+-deprecated({enter_loop, 6, next_major_release}).
+
-import(error_logger, [format/2]).
%%% ---------------------------------------------------
diff --git a/lib/stdlib/src/otp_internal.erl b/lib/stdlib/src/otp_internal.erl
index d89ff4a624..42094e3088 100644
--- a/lib/stdlib/src/otp_internal.erl
+++ b/lib/stdlib/src/otp_internal.erl
@@ -55,6 +55,55 @@ obsolete_1(erlang, now, 0) ->
obsolete_1(calendar, local_time_to_universal_time, 1) ->
{deprecated, {calendar, local_time_to_universal_time_dst, 1}};
+%% *** STDLIB added in OTP 20 ***
+
+obsolete_1(gen_fsm, start, 3) ->
+ {deprecated, {gen_statem, start, 3}};
+obsolete_1(gen_fsm, start, 4) ->
+ {deprecated, {gen_statem, start, 4}};
+
+obsolete_1(gen_fsm, start_link, 3) ->
+ {deprecated, {gen_statem, start, 3}};
+obsolete_1(gen_fsm, start_link, 4) ->
+ {deprecated, {gen_statem, start, 4}};
+
+obsolete_1(gen_fsm, stop, 1) ->
+ {deprecated, {gen_statem, stop, 1}};
+obsolete_1(gen_fsm, stop, 3) ->
+ {deprecated, {gen_statem, stop, 3}};
+
+obsolete_1(gen_fsm, enter_loop, 4) ->
+ {deprecated, {gen_statem, enter_loop, 4}};
+obsolete_1(gen_fsm, enter_loop, 5) ->
+ {deprecated, {gen_statem, enter_loop, 5}};
+obsolete_1(gen_fsm, enter_loop, 6) ->
+ {deprecated, {gen_statem, enter_loop, 6}};
+
+obsolete_1(gen_fsm, reply, 2) ->
+ {deprecated, {gen_statem, reply, 2}};
+
+obsolete_1(gen_fsm, send_event, 2) ->
+ {deprecated, {gen_statem, cast, 1}};
+obsolete_1(gen_fsm, send_all_state_event, 2) ->
+ {deprecated, {gen_statem, cast, 1}};
+
+obsolete_1(gen_fsm, sync_send_event, 2) ->
+ {deprecated, {gen_statem, call, 2}};
+obsolete_1(gen_fsm, sync_send_event, 3) ->
+ {deprecated, {gen_statem, call, 3}};
+
+obsolete_1(gen_fsm, sync_send_all_state_event, 2) ->
+ {deprecated, {gen_statem, call, 2}};
+obsolete_1(gen_fsm, sync_send_all_state_event, 3) ->
+ {deprecated, {gen_statem, call, 3}};
+
+obsolete_1(gen_fsm, start_timer, 2) ->
+ {deprecated, {erlang, start_timer, 2}};
+obsolete_1(gen_fsm, cancel_timer, 1) ->
+ {deprecated, {erlang, cancel_timer, 1}};
+obsolete_1(gen_fsm, send_event_after, 2) ->
+ {deprecated, {erlang, send_after, 2}};
+
%% *** CRYPTO added in OTP 20 ***
obsolete_1(crypto, rand_uniform, 2) ->