Re: rs232 under XP

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#10549

From: Benjamin Pratt
Date: Fri, 02 Apr 2004 17:56

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Reading and writing to the same handle _simultaneously_ is only possible
with overlapped I/O. Meaning reading/writing to the handle before a previous
read/write has completed. However, you can preform a read, then a write,
etc. so long as the previous operation has completed.
This is the crux of the problem that you were initially experiencing. The
WaitCommEvent had not completed yet, so the subsequent write would block
until WaitCommEvent finished. Now that you are using overlapped I/O, you can
use the same handle _simultaneously_ for two different operations.


"Martin" <anonymous@anonym.net> wrote in message
news:406d220c@newsgroups.borland.com...
> Hello Michel,
>
> I have BCB 5 and search the MS SDK that came with it.
>
> Under CreateFile, where they explain details about FILE_FLAG_OVERLAPPED is
> the following:
>
> This flag also enables more than one operation to be performed
> simultaneously with the handle (a simultaneous read and write operation,
for
> example).
>
> To me this means that it is not possible without overlap.
>
>
>
> Martin
>
>

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Subject: Re: rs232 under XP
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