.TH FLUSH 5.SH NAMEflush \- abort a message.SH SYNOPSIS.ta \w'\fLTflush 'u.IR size [4].B Tflush.IR tag [2].IR oldtag [2].br.IR size [4].B Rflush.IR tag [2].SH DESCRIPTIONWhen the response to a request is no longer needed, such as whena user interrupts a process doing a.IR sys-read (2),a.B Tflushrequest is sent to the server to purge the pending response.The message being flushed is identified by.IR oldtag .The semantics of.B flushdepends on messages arriving in order..PPThe server must answer the.B flushmessage immediately.If it recognizes.I oldtagas the tag of a pending transaction, it should abort any pending responseand discard that tag.In either case, it should respond with an.B Rflushechoing the.I tag(not.IR oldtag )of the.B Tflushmessage.A.B Tflushcan never be responded to by an.B Rerrormessage..PPWhen the client sends a .BR Tflush ,it must wait to receive the corresponding.B Rflushbefore reusing.I oldtagfor subsequent messages.If a response to the flushed request is received before the.BR Rflush ,the client must honor the responseas if it had not been flushed,since the completed request may signify a state change in the server.For instance,.B Tcreatemay have created a file and.B Twalkmay have allocated a fid.If no response is received before the.BR Rflush ,the flushed transaction is considered to have been cancelled,and should be treated as though it had never been sent..PPSeveral exceptional conditions are handled correctly by the above specification:sending multiple flushes for a single tag,flushing after a transaction is completed,flushing a.BR Tflush ,and flushing an invalid tag..SH SEE ALSO.IR sys-read (2).