[REBOL] Re: pop problems
From: gscottjones:mchsi at: 16-Oct-2002 15:57
Hi, Graham,
From: "Graham Chiu"
message: http://www.escribe.com/internet/rebol/m26582.html
...
> I tracked the problem down to
>
> read-til-dot: func [port buf][
> while [(line: system/words/pick port/sub-port 1) <>
> "."] [
> if none? line [ print "Got none .. aborting" break
> ]
> insert tail buf line
> insert tail buf newline
> ]
> buf
> ]
>
> where /pick port 1 returns none ... and keeps returning
> none in an endless loop.
>
> I put the above trap in the function, but then get a tcp
> error, as can be seen when I then do
>
> pick mailbox 2
>
> Does anyone knowledgeable in matters Rebol tcp have a work
> round for me?
Getting none on the port suggests an error that is not necessarily
originating from REBOL. (Maybe you weren't implying it is a REBOL problem.
:-) The POP protocol says that for multiline messages, that the message is
sent and then a single line with a period is sent. A none return suggests a
pop server error or dropped packets/congestion. At any rate, if you are
checking for this state in order to debug the whole situation, then I think
your way will work, but the function needs to return a value in order to
avoid an error. Try something like:
func [port buf][
while [(line: system/words/pick port/sub-port 1) <> "."] [
if none? line [
print "Got none .. aborting"
break/return buf
]
insert tail buf line
insert tail buf newline
]
buf
]
where the break returns the buffer named buf. This should avoid an error.
If it is some sort of network congestion problem, then I will guess that you
may likely see other shortened messages due to a premature abortion on the
port read (meaning there was momentarily nothing to be read).
Experimentation will readily reveal if this is a problem.
Good luck, and hope my mini-fix avoids the error.
--Scott Jones
