diff options
Diffstat (limited to 'lib/stdlib/test/shell_docs_SUITE_data/unknown_erlang_monitor_3_func.txt')
| -rw-r--r-- | lib/stdlib/test/shell_docs_SUITE_data/unknown_erlang_monitor_3_func.txt | 80 |
1 files changed, 79 insertions, 1 deletions
diff --git a/lib/stdlib/test/shell_docs_SUITE_data/unknown_erlang_monitor_3_func.txt b/lib/stdlib/test/shell_docs_SUITE_data/unknown_erlang_monitor_3_func.txt index 35cab15b0d..d2568b9d01 100644 --- a/lib/stdlib/test/shell_docs_SUITE_data/unknown_erlang_monitor_3_func.txt +++ b/lib/stdlib/test/shell_docs_SUITE_data/unknown_erlang_monitor_3_func.txt @@ -10,7 +10,7 @@ [;1m when MonitorRef :: reference().[0m [;;4mSince[0m: - OTP @OTP-16718@ + OTP 24.0 Types: -type monitor_port_identifier() :: port() | registered_name(). @@ -59,8 +59,86 @@ removed using the [;;4munalias/1[0m BIF, the monitor will still be left active. + Example: + + server() -> + receive + {request, AliasReqId, Request} -> + Result = perform_request(Request), + AliasReqId ! {reply, AliasReqId, Result} + end, + server(). + + client(ServerPid, Request) -> + AliasMonReqId = monitor(process, ServerPid, [{alias, reply_demonitor}]), + ServerPid ! {request, AliasMonReqId, Request}, + %% Alias as well as monitor will be automatically deactivated if we + %% receive a reply or a 'DOWN' message since we used 'reply_demonitor' + %% as unalias option... + receive + {reply, AliasMonReqId, Result} -> + Result; + {'DOWN', AliasMonReqId, process, ServerPid, ExitReason} -> + error(ExitReason) + end. + + + Note that both the server and the client in this example must + be executing on at least OTP 24 systems in order for this to + work. + + For more information on process aliases see the Process + Aliases section of the Erlang Reference Manual. + [;;4m[;;4m{tag, UserDefinedTag}[0m[0m: Replace the default [;;4mTag[0m with [;;4mUserDefinedTag[0m in the monitor message delivered when the monitor is triggered. For example, when monitoring a process, the [;;4m'DOWN'[0m tag in the down message will be replaced by [;;4mUserDefinedTag[0m. + + An example of how the [;;4m{tag, UserDefinedTag}[0m option can be + used in order to enable the new selective receive + optimization, introduced in OTP 24, when making multiple + requests to different servers: + + server() -> + receive + {request, From, ReqId, Request} -> + Result = perform_request(Request), + From ! {reply, self(), ReqId, Result} + end, + server(). + + client(ServerPids, Request) when is_list(ServerPids) -> + ReqId = make_ref(), + lists:foreach(fun (ServerPid) -> + _ = monitor(process, ServerPid, + [{tag, {'DOWN', ReqId}}]), + ServerPid ! {request, self(), ReqId, Request} + end, + ServerPids), + receive_replies(ReqId, length(ServerPids), []). + + receive_replies(_ReqId, 0, Acc) -> + Acc; + receive_replies(ReqId, N, Acc) -> + %% The compiler will detect that we match on the 'ReqId' + %% reference in all clauses, and will enable the selective + %% receive optimization which makes the receive able to + %% skip past all messages present in the message queue at + %% the time when the 'ReqId' reference was created... + Res = receive + {reply, ServerPid, ReqId, Result} -> + %% Here we typically would have deactivated the + %% monitor by a call to demonitor(Mon, [flush]) but + %% we ignore this in this example for simplicity... + {ok, ServerPid, Result}; + {{'DOWN', ReqId}, _Mon, process, ServerPid, ExitReason} -> + {error, ServerPid, ExitReason} + end, + receive_replies(ReqId, N-1, [Res | Acc]). + + + In order for this example to work as intended, the client must + be executing on at least an OTP 24 system, but the servers may + execute on older systems. |