@InProceedings{Teig12,
  title =        "{XCHAN}s: {N}otes on a {N}ew {C}hannel {T}ype",
  author=        "Teig,  Øyvind",
  editor=        "Welch, Peter H. and Barnes,  Frederick R. M. and Chalmers,  Kevin and Pedersen,  Jan Bækgaard and Sampson,  Adam T.",
  pages =        "155--170",
  booktitle=     "{C}ommunicating {P}rocess {A}rchitectures 2012",
  isbn=          "978-0-9565409-5-9",
  year=          "2012",
  month=         "aug",
  abstract=      "This paper proposes a new channel type, XCHAN, for
     communicating
messages between a sender and receiver.
     Sending on an XCHAN is
asynchronous, with the sending
     process informed as to its success.
XCHANs may be buffered,
     in which case a successful send means the
message has got
     into the buffer.  A successful send to an unbuffered
XCHAN
     means the receiving process has the message. In either case,
     a
failed send means the message has been discarded. If
     sending on an XCHAN
fails, a built-in feedback channel (the
     x-channel, which has
conventional channel semantics) will
     signal to the sender when the
channel is ready for input
     (i.e., the next send will succeed). This
x-channel may be
     used in a select or ALT by the sender side (only
     input
guards are needed), so that the sender may passively
     wait for this
notification whilst servicing other events.
     When the x-channel signal is
taken, the sender should send
     as soon as possible -- but it is free to
send something
     other than the message originally attempted (e.g.
     some
freshly arrived data). The paper compares the use of
     XCHAN with the use
of output guards in select/ALT
     statements. XCHAN usage should follow a
design pattern,
     which is also described. Since the XCHAN never blocks,
its
     use contributes towards deadlock- avoidance. The XCHAN
     offers one
solution to the problem of overflow handling
     associated with a fast
producer and slow consumer in message
     passing systems. The claim is that
availability of XCHANs
     for channel based systems gives the designer and
programmer
     another means to simplify and increase quality."
}