diff options
| -rw-r--r-- | system/doc/design_principles/events.xml | 17 | ||||
| -rw-r--r-- | system/doc/design_principles/fsm.xml | 5 | ||||
| -rw-r--r-- | system/doc/design_principles/gen_server_concepts.xml | 5 |
3 files changed, 27 insertions, 0 deletions
diff --git a/system/doc/design_principles/events.xml b/system/doc/design_principles/events.xml index 5579f1e459..fab9e8305e 100644 --- a/system/doc/design_principles/events.xml +++ b/system/doc/design_principles/events.xml @@ -217,5 +217,22 @@ terminate(_Args, Fd) -> ok</pre> </section> </section> + <section> + <title>Handling Other Messages</title> + <p>If the gen_event should be able to receive other messages than + events, the callback function <c>handle_info(Info, StateName, StateData)</c> + must be implemented to handle them. Examples of + other messages are exit messages, if the gen_event is linked to + other processes (than the supervisor) and trapping exit signals.</p> + <code type="none"> +handle_info({'EXIT', Pid, Reason}, State) -> + ..code to handle exits here.. + {ok, NewState}.</code> + <p>The code_change method also has to be implemented.</p> + <code type="none"> +code_change(OldVsn, State, Extra) -> + ..code to convert state (and more) during code change + {ok, NewState}</code> + </section> </chapter> diff --git a/system/doc/design_principles/fsm.xml b/system/doc/design_principles/fsm.xml index 7cdd62057b..c3e9027274 100644 --- a/system/doc/design_principles/fsm.xml +++ b/system/doc/design_principles/fsm.xml @@ -308,6 +308,11 @@ terminate(normal, _StateName, _StateData) -> handle_info({'EXIT', Pid, Reason}, StateName, StateData) -> ..code to handle exits here.. {next_state, StateName1, StateData1}.</code> + <p>The code_change method also has to be implemented.</p> + <code type="none"> +code_change(OldVsn, StateName, StateData, Extra) -> + ..code to convert state (and more) during code change + {ok, NextStateName, NewStateData}</code> </section> </chapter> diff --git a/system/doc/design_principles/gen_server_concepts.xml b/system/doc/design_principles/gen_server_concepts.xml index 8131c47a69..231333da0e 100644 --- a/system/doc/design_principles/gen_server_concepts.xml +++ b/system/doc/design_principles/gen_server_concepts.xml @@ -264,6 +264,11 @@ terminate(normal, State) -> handle_info({'EXIT', Pid, Reason}, State) -> ..code to handle exits here.. {noreply, State1}.</code> + <p>The code_change method also has to be implemented.</p> + <code type="none"> +code_change(OldVsn, State, Extra) -> + ..code to convert state (and more) during code change + {ok, NewState}.</code> </section> </chapter> |