How to start multiple instances of the same module/function under the Supervisor behavior in erlang? -

having module/function mymodule , how start multiple times under supervisor behavior ?

i need example 2 instances of same process (mymodule) started concurrently. called children identifiers child1 , child2. both point mymodule module want start. have specified 2 different functions to start each instance of worker process "mymodule" ( start_link1 , start_link2 )

-module(my_supervisor).  -behaviour(supervisor).  -export([start_link/0, init/1]).  start_link() ->     supervisor:start_link({local, ?module}, ?module, _arg = []).  init([]) ->     {ok, {{one_for_one, 10, 10},           [{child1,             {mymodule, start_link1, []},             permanent,             10000,             worker,             [mymodule]}           ,            {child2,             {mymodule, start_link2, []},             permanent,             10000,             worker,             [mymodule]}           ]}}. 

the worker has 2 distinguished start_link functions ( start_link1 , start_link2 ) testing purposes:

-module(mymodule). -behaviour(gen_server).  start_link1() ->     log_something("at link 1"),     gen_server:start_link({global, child1}, ?module, [], []).  start_link2() ->     log_something("at link 2"),     gen_server:start_link({global, child2}, ?module, [], []).  init([]) ->     .... 

with above can see in log message "at link 1" reveal "at link 2" anywhere. not perform in instance of link1 : dies apparently.

the scenario works when name "child1" matches worker module name "mymodule".

as @millebessö asks trying 2 processes have same registered name? mymodule:start_link register mymodule process under fixed name? if trying start second 1 cause clash. ot trying start multiple my_supervisor supervisors? name clash. have not included code my_module.

remember can have 1 process registered under name. holds both local registered processes , registered using global.

edit: supervisor die well?

a gen_server, , other behaviours, aren't considered started until init callback has completed , returned correct value ({ok,state}). if there error in mymodule:init/1 crash child process before has been initialised , supervisor give up. while supervisor can , restart children when die require start correctly. supervisor:start_link/3

if supervisor , child processes created (i.e. if child process start functions return {ok,child}, {ok,child,info}, or ignore) function returns {ok,pid}, pid pid of supervisor. if there exists process specified supname function returns {error,{already_started,pid}}, pid pid of process.

if module:init/1 returns ignore, function returns ignore , supervisor terminates reason normal. if module:init/1 fails or returns incorrect value, function returns {error,term} term term information error, , supervisor terminates reason term.

i don't know if problem give same behaviour get.