[erlang-questions] Supervision Tree

Bengt Kleberg <>
Wed Nov 28 11:34:35 CET 2012


Greetings,

First let me mention that I prefer to never mix call back code that runs
in a special process (in this case the supervision process) with code
used by other processes. So, start_link/0 is better off in another
module.

Secondly, if you have a variable with _ first in the name the compiler
should not complain about it not being used. What is your compile
command?

Last, _Args is the [] from supervisor:start_link/2


ebngt

On Wed, 2012-11-28 at 12:23 +0200, Lucky Khoza wrote:
> Hi Erlang Developers,
> 
> I'm actually trying to understand and compile the following module
> code, and i don't understand why the init/1 function takes an argument
> which it doesn't use at all, so when i try to compile the module it
> complains about the argument _Args because it's unused.
> 
> May someone help me understand the use of this argument?
> 
> -module(ch_sup).
> -behaviour(supervisor).
> 
> -export([start_link/0]).
> -export([init/1]).
> 
> start_link() ->
>     supervisor:start_link(ch_sup, []).
> 
> init(_Args) ->
>     {ok, {{one_for_one, 1, 60},
>           [{ch3, {ch3, start_link, []},
>             permanent, brutal_kill, worker, [ch3]}]}}.
> 
> 
> Thanks for a lot for your help, i really appreciate it.
> Kindest Regards
> Lucky
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