[erlang-questions] variable unbound

Robert Virding <>
Thu Apr 2 13:15:26 CEST 2009


2009/4/2 Gamoto <>

> What is wrong in this function ? I receive the following error: variable
> 'S' is unbound !
> I also receive two warnings: File is unused, S is unused.
> This process can receive two messages: one file to open and one message to
> write
>
> Pid ! {open,"filetoopen.txt"}
>
> Pid ! {data, Message}
>
> log_message()->
>    receive
>                {open,File} -> case file:open("File", [append]) of
>                                                        {ok,S} ->
>  log_message();
>                                    {error,Reason} -> io:format(
> "~s~n",[Reason])
>                                    end;
>                {data,Data} ->  io:format(S,"~s~n",[Data]),
>                                                  log_message()
>   end.


- The variable File is defined in the message {file,File} you recieve but is
never used, you open the file "File".

- The variable S is defined when you receive the {open,File} message, but
you wish to use it when you receive the {data,Data} message where it is not
defined.

Robert
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