问题
I have gen_server:
start(UserName) ->
case gen_server:start({global, UserName}, player, [], []) of
{ok, _} ->
io:format("Player: " ++ UserName ++ " started");
{error, Error} ->
Error
end
...
Now i want to write function to stop this gen server. I have:
stop(UserName) ->
gen_server:cast(UserName, stop).
handle_cast(stop, State) ->
{stop, normal, State};
handle_cast(_Msg, State) ->
{noreply, State}.
I run it:
start("shk").
Player: shk startedok
stop(shk).
ok
start("shk").
{already_started,<0.268.0>}
But:
stop(player).
ok
is work.
How can i run gen_server by name and stop by name?
Thank you.
回答1:
First: You must always use the same name to address a process, "foo"
and foo
are different, so start by having a strict naming convention.
Second: When using globally registered processes, you also need to use {global, Name}
for addressing processes.
In my opinion you should also convert the stop
function to use gen_server:call
, which will block and let you return a value from the gen_server. An example:
stop(Name) ->
gen_server:call({global, Name}, stop).
handle_call(stop, _From, State) ->
{stop, normal, shutdown_ok, State}
This would return shutdown_ok
to the caller.
With this said, the global
module is rather limited and alternatives like gproc
provides much better distribution.
回答2:
I don't have the docs infront of me, but my guess would be that you need to wrap the username in a global tuple within the gen_server cast.
来源:https://stackoverflow.com/questions/5726481/erlang-stop-gen-server