[erlang-questions] {badarg, [{code_server, call, 2}, {error_handler, undefined_function, 3}]}

[Bernard Duggan]

Two ways spring to mind.

The first is to create it as a linked process using spawn_link() rather
than spawn() (or by subsequently calling link()).  Then, when the
process that spawned it dies, it will die too.  Of course, the reverse
is also true (the spawning process will die if the spawned one exists)
unless it has trap_exit enabled.

The other is to call exit(SpawnedPid, Reason) where 'Reason' is
something other than 'normal'.

There's probably other ways too that I can't think of right now (besides
just shutting down the whole vm of course).

Cheers,

Bernard

David Tucker wrote:
> Thanks for the info.  Is there a clean way to shut down a process that
> is blocking on io:get_line()?
>
> Dave
>
>
> On Mon, Dec 8, 2008 at 10:08 PM, Bernard Duggan <bernie@REDACTED
> <mailto:bernie@REDACTED>> wrote:
>
>     While someone else can probably explain exactly why you're getting
>     that
>     particular message (I could guess, but I'd probably get it wrong),
>     I can
>     at least tell you why your test isn't working :)
>     The use of "-s init stop" tells the erts to execute "init:stop" as
>     soon
>     as the previous function ("inp:start") returns.  The problem you're
>     having is that inp:start spawns a thread and returns straight
>     away.  The
>     erts then calls init:stop, killing off the whole elang vm (and,
>     presumably, creating some kind of error condition in the remaining
>     thread which is the output you're seeing).
>     You need to either have inp:start wait until its child process has
>     completed (perhaps with a 'receive' block), or not tell the vm to shut
>     down using "-s init stop".
>
>     Hope that's some help.
>
>     Cheers,
>
>     Bernard
>
>     David Tucker wrote:
>     > Hi folks,
>     >
>     > My simple program below gives an error on exit.  Any idea what is
>     > wrong?  Thanks.
>     >
>     > Dave
>     >
>     > ---
>     >
>     > $ cat inp.erl
>     > -module(inp).
>     > -compile(export_all).
>     >
>     > start() ->
>     >     spawn(fun() -> one_line() end).
>     >
>     > one_line() ->
>     >     case io:get_line("") of
>     >      Str -> lib:nonl(Str)
>     >     end.
>     > $ erlc inp.erl
>     > $ erl -noshell -s inp start -s init stop
>     > {error_logger,{{2008,12,8},{21,39,50}},"~s~n",["Error in process
>     > <0.28.0> with exit value:
>     >
>     {badarg,[{code_server,call,2},{error_handler,undefined_function,3}]}\n"]}
>     > $ port info erlang | head -1
>     > erlang R12B-5, lang/erlang (Variants: universal, smp, ssl, hipe,
>     i386)
>     >
>     >
>     ------------------------------------------------------------------------
>     >
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