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In lugnet.robotics.rcx.pbforth, Ralph Hempel wrote:
> > Ralph, one more question. Are there conditions where the word EKEY would wait
> > for input (like KEY)? It seems to happen in my program.
>
> EKEY always waits for input. Use EKEY? to see if anything is available...
>
> Looking at the source, I see that there is a possiblity that in the time
> between checking for a character with EKEY? and actually reading
> it with EKEY, that an error can occur and casue EKEY to block even
> though you think it should not.
>
> You should always use EKEY? before EKEY, but traditional Forth does not
> let you check for errors in EKEY so...
>
> How should we handle this? I can make a new word that returns the actual
> byte in the low order bits and additional info in the high byte...
>
> If the high byte is 0, then there is no data.
>
> What should we call the word?
>
> Ralph
I did not explain my problem properly but you got it anyway! I do use EKEY?
before EKEY, but sometimes EKEY seems to block. Thanks for taking your time to
look into this.
As for the new word (wow!), in Forth-79, there was a word called ?KEY
that scanned the keyboard and returned 0 if no key was pressed or the ascii code
of the character. Can we go that way?
Thank you very much.
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Message is in Reply To:
 | | RE: IR problems
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| (...) EKEY always waits for input. Use EKEY? to see if anything is available... Looking at the source, I see that there is a possiblity that in the time between checking for a character with EKEY? and actually reading it with EKEY, that an error can (...) (21 years ago, 30-Jan-04, to lugnet.robotics.rcx.pbforth)
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