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Date: Tue, 22 Aug 2006 09:40:40 -0400 (EDT)
From: Igor Peshansky <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: Ernesto Paiser <paiser AT esrf DOT fr>
cc: cygwin AT cygwin DOT com
Subject: Re: read()  blocking and TIOCINQ
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On Tue, 22 Aug 2006, Ernesto Paiser wrote:

> Hello Corinna,

FYI, this is a mailing list, and unless you're replying to a specific
message, you're actually talking to many people.

> I have problems with read() function blocking and
> waiting for characters on serial line with cygwin:
>
> Here are some code fragments:
> ========================================================
> fd = open(sl, O_RDWR | O_NOCTTY | O_NONBLOCK | O_NDELAY)
>
> newpio.c_cflag = brate | CS8 | CLOCAL | CREAD;
> newpio.c_iflag = IGNPAR | ICRNL;
> newpio.c_oflag = 0;
> newpio.c_lflag = 0;
> newpio.c_cc[VTIME]    = 1;
> newpio.c_cc[VMIN]     = 0;
> ...
>
> n = ioctl(fd, TIOCINQ, &n); //It gives me an error (return -1) why??!!!
>
> and
>
> n = read(fd, buffer, 1);  <<< HERE IS BLOCKING!!!
> ========================================================
>
> TIOCINQ is working on CYGWIN,
>
> Is there another way to solve this problem???

Please post a complete compilable test case that reproduces the problem.
For example, in the above code, it's unclear what the variable sl contains
(and I suspect it contains "COM1", which is a no-no -- you should be using
"/dev/ttyS0").
	Igor
-- 
				http://cs.nyu.edu/~pechtcha/
      |\      _,,,---,,_	    pechtcha AT cs DOT nyu DOT edu | igor AT watson DOT ibm DOT com
ZZZzz /,`.-'`'    -.  ;-;;,_		Igor Peshansky, Ph.D. (name changed!)
     |,4-  ) )-,_. ,\ (  `'-'		old name: Igor Pechtchanski
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

"Las! je suis sot... -Mais non, tu ne l'es pas, puisque tu t'en rends compte."
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