[erlang-questions] dumb question from rookie

envelopes envelopes <>
Tue Mar 6 08:32:25 CET 2012


Another interesting thing is : though erl -pa ebin -s application start
mysample works, mysample_app is not listed in loaded modules from shell
command m().

???



On Mon, Mar 5, 2012 at 10:34 PM, envelopes envelopes
<>wrote:

> weird.
>
> Why "erl -pa ebin -s mysample_app start x y" doesn't work, but  "erl -pa
> ebin -s application start mysample" works,
>
> is it a bug in erlang?
>
>
> On Mon, Mar 5, 2012 at 10:21 PM, Ryan Huffman <>wrote:
>
>> It looks like you are trying to call your state function with 0
>> arguments, but the start function has an arity of 2 (it expects 2
>> arguments).  You can add 2 dummy arguments or use `-s application start
>> mysample` instead.
>>
>> On Monday, March 5, 2012 at 10:07 PM, envelopes envelopes wrote:
>>
>>
>> I have a sample program generated from rebar
>>
>> 1. mysample_app.erl
>>
>> -module(mysample_app).
>>
>> -behaviour(application).
>>
>> %% Application callbacks
>> -export([start/2, stop/1, main/1]).
>>
>> %% ===================================================================
>> %% Application callbacks
>> %% ===================================================================
>>
>> start(_StartType, _StartArgs) ->
>>     mysample_sup:start_link().
>>
>> stop(_State) ->
>>     ok.
>>
>>
>> main([A]) ->
>> I = list_to_integer(atom_to_list(A)),
>> F = fac(I),
>> io:format("factorial ~w = ~w~n" ,[I, F]),
>> init:stop().
>> fac(0) -> 1;
>> fac(N) -> N*fac(N-1).
>>
>>
>> 2. mysample_sup.erl
>>
>>
>> -module(mysample_sup).
>>
>> -behaviour(supervisor).
>>
>> %% API
>> -export([start_link/0]).
>>
>> %% Supervisor callbacks
>> -export([init/1]).
>>
>> %% Helper macro for declaring children of supervisor
>> -define(CHILD(I, Type), {I, {I, start_link, []}, permanent, 5000, Type,
>> [I]}).
>>
>> %% ===================================================================
>> %% API functions
>> %% ===================================================================
>>
>> start_link() ->
>>     supervisor:start_link({local, ?MODULE}, ?MODULE, []).
>>
>> %% ===================================================================
>> %% Supervisor callbacks
>> %% ===================================================================
>>
>> init([]) ->
>>     {ok, { {one_for_one, 5, 10}, []} }.
>>
>>
>> 3) the problem.
>> erl -pa ebin -s mysample_app main 23  ===> worked fine
>> erl -pa ebin -s mysample_app start   ===> crashed on boot.
>>
>> {"init terminating in
>> do_boot",{undef,[{mysample_app,start,[],[]},{init,start_it
>>
>> ,1,[{file,"init.erl"},{line,1042}]},{init,start_em,1,[{file,"init.erl"},{line,10
>> 22}]}]}}
>>
>> Crash dump was written to: erl_crash.dump
>> init terminating in do_boot ()
>>
>> what is the cause ? my erlang is the latest R15.
>> _______________________________________________
>> erlang-questions mailing list
>> 
>> http://erlang.org/mailman/listinfo/erlang-questions
>>
>>
>>
>
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