[erlang-questions] variable unbound
Gamoto
gamoto@REDACTED
Thu Apr 2 14:57:34 CEST 2009
I don't understand. After the reception of the filename the variable S is defined !
I could understand a run-time error if I send a message before to send the filename !!
2009/4/2 Gamoto <gamoto@REDACTED>
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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