diff options
Diffstat (limited to 'lib/stdlib')
| -rw-r--r-- | lib/stdlib/doc/src/gen_statem.xml | 89 |
1 files changed, 62 insertions, 27 deletions
diff --git a/lib/stdlib/doc/src/gen_statem.xml b/lib/stdlib/doc/src/gen_statem.xml index be0d64feba..252a8370ad 100644 --- a/lib/stdlib/doc/src/gen_statem.xml +++ b/lib/stdlib/doc/src/gen_statem.xml @@ -32,39 +32,43 @@ <modulesummary>Generic state machine behavior.</modulesummary> <description> <p> - This behavior module provides a state machine. Two - <seealso marker="#type-callback_mode"><em>callback modes</em></seealso> - are supported: + <c>gen_statem</c> provides a generic state machine behaviour + and replaces its predecessor + <seealso marker="gen_fsm"><c>gen_fsm</c> </seealso> + since Erlang/OTP 20.0. + </p> + <p> + This reference manual describes types generated from the types + in the <c>gen_statem</c> source code, so they are correct. + However, the generated descriptions also reflect the type hiearchy, + which makes them kind of hard to read. + </p> + <p> + To get an overview of the concepts and operation of <c>gen_statem</c>, + do read the + <seealso marker="doc/design_principles:statem">User's Guide</seealso>. + It frequently links back to this reference manual to avoid containing + detailed facts that may rot by age. </p> - <list type="bulleted"> - <item> - <p>One for finite-state machines - (<seealso marker="gen_fsm"><c>gen_fsm</c></seealso> like), - which requires the state to be an atom and uses that state as - the name of the current callback function - </p> - </item> - <item> - <p>One without restriction on the state data type - that uses one callback function for all states - </p> - </item> - </list> <note> <p> - This is a new behavior in Erlang/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. - Depending on user feedback, we do not expect - but can find it necessary to make minor - not backward compatible changes into Erlang/OTP 20.0. + This behavior appeared in Erlang/OTP 19.0. + In OTP 19.1 a backwards incompatible change of + the return tuple from + <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso> + was made and the mandatory callback function + <seealso marker="#Module:callback_mode/0"> + <c>Module:callback_mode/0</c> + </seealso> + was introduced. In OTP 20.0 the + <seealso marker="#type-generic_timeout"><c>generic timeouts</c></seealso> + were added. </p> </note> <p> - 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: + <c>gen_statem</c> has got the same features that + <seealso marker="gen_fsm"><c>gen_fsm</c> </seealso> + had and adds some really useful: </p> <list type="bulleted"> <item>Gathered state code.</item> @@ -78,6 +82,27 @@ <item>Reply from other state than the request.</item> <item>Multiple <c>sys</c> traceable replies.</item> </list> + + + <p> + Two + <seealso marker="#type-callback_mode"><em>callback modes</em></seealso> + are supported: + </p> + <list type="bulleted"> + <item> + <p>One for finite-state machines + (<seealso marker="gen_fsm"><c>gen_fsm</c></seealso> like), + which requires the state to be an atom and uses that state as + the name of the current callback function + </p> + </item> + <item> + <p>One without restriction on the state data type + that uses one callback function for all states + </p> + </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>, @@ -252,6 +277,16 @@ erlang:'!' -----> Module:StateName/3 to use after every event; see <seealso marker="erts:erlang#hibernate/3"><c>erlang:hibernate/3</c></seealso>. </p> + <p> + There is also a server start option + <seealso marker="#type-hibernate_after_opt"> + <c>{hibernate_after, Timeout}</c> + </seealso> + for + <seealso marker="#start/3"><c>start/3,4</c></seealso> or + <seealso marker="#start_link/3"><c>start_link/3,4</c></seealso> + that may be used to automatically hibernate the server. + </p> </description> <section> |