FLUSH(5) FLUSH(5)
NAME
flush - abort a message
SYNOPSIS
Tflush tag[2] oldtag[2]
Rflush tag[2]
DESCRIPTION
When the response to a request is no longer needed, such as
when a user interrupts a process doing a sys-read(2), a
Tflush request is sent to the server to purge the pending
response. The message being flushed is identified by
oldtag. The semantics of flush depends on messages arriving
in order.
The server must answer the flush message immediately. If it
recognizes oldtag as the tag of a pending transaction, it
should abort any pending response and discard that tag. In
either case, it should respond with an Rflush echoing the
tag (not oldtag) of the Tflush message. A Tflush can never
be responded to by an Rerror message.
When the client sends the Tflush, it should disregard all
messages received with tag oldtag until the corresponding
Rflush is received, at which point oldtag may be recycled
for subsequent messages.
Several exceptional conditions are handled correctly by the
above specification: sending multiple flushes for a single
tag, flushing a Tflush, and flushing an invalid tag.
SEE ALSO
sys-read(2).
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