[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Bad change in counted array protocol?



I’ve passed this on to Conor himself, I happened to see him today.

Roger

> On 6 Dec 2018, at 15:33, Larry Dickson <tjoccam@xxxxxxxxxxx> wrote:
> 
> All,
> 
> I took a look in detail at the definition of occam 2.5 in Conor O'Neill's document
> 
> http://wotug.org/occam/documentation/oc21small.pdf
> 
> and I found this:
> 
> ======
> 19 Counted array input . . . A counted array input of the form
> 
> message ? len :: buffer
> 
> is no longer permitted to refer to the len as part of the expression buffer.
> Note: This is a change from strict occam 2 behavior.
> 
> 19.2 Rationale
> 
> This makes it possible to treat the input at a single input . . .
> ======
> 
> He makes a concession to previous usage but makes it clear it is vacuous.
> 
> This appears to make no sense. If len is an unknown-ahead-of-time value,
> shorter than the target array, then it appears that (a) this opens the door
> to buffer overflows, (b) in the "move" type of input, the inputting process
> cannot know the size of the move, (c) in a link input, the link will not know
> when the transmission is done and therefore will not know when to
> reschedule the process.
> 
> Did this change get adopted, i.e. put into occam-pi or any other
> subsequent version of occam? It appears to destroy the entire purpose of
> counted array protocol.
> 
> Larry Dickson

--
Roger Shepherd
rog@xxxxxxxx




Attachment: signature.asc
Description: Message signed with OpenPGP