Yannick
Thu Feb 03 01:49:27 CST 2005
On Win32, when using ReadFile and WriteFile, you can pass an optional
parameter which is an OverlapIo struct. this struct allow you giving an
HEVENT to the system so that your ReadFile/WriteFile would not be blocking
(especially for ReadFile, if you ask for a nr of characters that are not
available immediately). The call will be non blocking, and you'll be
notified of completion through the HEVENT you specified.
Under CE, you can't use this way of working, which means that Overlap prm is
not handled, and that all your calls will be blocking (example, if you
perform a read of n characters on a serial link, you won't exit Readfile
call before receiving the n characters or timeout)
--
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Yannick Chamming's (eMVP)
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"Manoj" <Manoj@discussions.microsoft.com> wrote in message
news:AD27475E-4DE4-44EE-839D-395225B4785F@microsoft.com...
> hai,
> it is heard that " To minimize the size of the filesys
component,windows
> ce only support Synchronous file acess,This is the reason why overlapped
I/O
> is not supported...
> can anyone explain what is this synchronous file access and
overlapped
> i/o..
> The statement implies that other windows os have both asynchronous access
> and overlapped i/o....
> Does it mean in the following way..
>
> asynchronous => means multiple file access can be done..overlapped i/o is
> the same,isn't it...otherwise tell me
>
> Expecting ur early responce
>
>
>
> thanking u
>
>