Problem using select() with com0com virtual serial ports

[Christopher Faylor]

On Sat, Jan 24, 2009 at 03:30:34PM -0500, Paul Ingemi wrote:
>* On Thu, Jan 22, 2009 at 10:55:22AM -0500 Christopher Faylor wrote:
>> On Thu, Jan 22, 2009 at 10:25:32AM -0500, Paul Ingemi wrote:
>[...]
>> It is a simple enough hack that I don't mind adding it, if it fixes your
>> problem but I am not convinced that your driver is operating correctly.
>>
>> As I had added serial port access to the Windows version of VICE one or
>> two months ago, I can tell that the com0com driver is indeed buggy.
>>
>> IMHO, the better solution is to fix com0com, and not to apply some
>> hotfixes to other software (cygwin, VICE, whatever). That's the approach
>> I followed, too, ignoring com0com completely. If I might have some time,
>> I might want to debug com0com myself, but don't hold your breath on it.
>
>I agree and adding a hack to cygwin isn't necessary due to the
>existance of a workaround. That said, I think it's premature to blame
>com0com without finding the root cause of the problem.
>
>Over the past two days I've been attempting to create an -mno-cygwin
>executable that can reproduce the behavior I'm seeing under Cygwin.
>Thus far I haven't successfully reproduced this behavior outside of a
>Cygwin environment despite copying most of the code for how Cygwin
>performs select() and read().

I don't really see why it is necessary to stand you your head here.
Your change added a function call which, as far as I can tell from
documentation, should be a no-op.  The change is not required for normal
serial operation.  To me, that shows pretty clearly that com0com is
doing something nonstandard.

cgf

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