net-select and seripal port

[dexter]

I use net-select on serial port



check if it is ready to read data



I use stty to set serial port first

then open it with "non-block" option

Code Select Expand


(define (read_proc)

    (setq rusbdev (open dev "r" "n"))
    (if (nil? rusbdev)
        (begin
            (println "open " dev " read failed")
            (exit rusbdev)
       )
    )

    (until  (= (share talk) 3)  ;; for stoping and exiting
            (while (and (net-select rusbdev "read" 10000) (> (peek rusbdev) 0) )

                (setq read_ret (read_serial rusbdev) )
                (share content read_ret)
                (println "in read_proc " (share content))
            )
            (sleep 80)
    )
    (close rusbdev)
    (exit 0)
)



the share parts are  not important

I use share memory to send read results back to writing process



I forked a process to do reading stuff, and send results back to main process, the writing process.



but it seems net-select return at once, without waiting for like 10000ms



I know it's kind of wired , But I need a "function" like select



Maybe I can set something ,so make serial port dev fd to work like socket fd



Can I do that in newlisp?



BTW: this works, but not perfect, somehow, the speed of read is too fast, so it will might read twice on a

very short data

That's not I wanted

I want read the whole data from serial port at one time.

When I add (sleep 80) at the bottom of this function, it work maybe perfect at the most of time

But I am not sure (sleep) is the perfect ,safest way. I  think

the number of ms in (sleep) is depend on the performance of my serial device

If my device is faster, then I maybe sleep less

otherwise, more

So I think select(net-select) is the smart way, right?

[Lutz]

On Mac OSX and other UNIX use peek :

http://www.newlisp.org/downloads/newlisp_manual.html#peek">http://www.newlisp.org/downloads/newlis ... .html#peek">http://www.newlisp.org/downloads/newlisp_manual.html#peek

[dexter]

But peek wont wait  like select or wait forever?



So peek + sleep is the option?



Is this ways  good enough as select?