problem with readonly pinfo?

Corinna Vinschen
Wed Sep 17 20:03:00 GMT 2003

On Wed, Sep 17, 2003 at 03:41:34PM -0400, Christopher Faylor wrote:
> On Wed, Sep 17, 2003 at 08:23:42PM +0200, Corinna Vinschen wrote:
> >Weird enough, they implemented overlapped IO for named pipes.  Just for
> >anonymous pipes (and therefore not on 9x/Me) it's not implemented.
> Yeah.  Have you ever tested overlapped I/O on regular pipes on NT?  I think
> I have but I don't remember the results.  I've suspected that anonymous pipes
> are just named pipes under the hood.

Anonymous pipes are actually named pipes under NT.  That's documented
in MSDN.  Unfortunately, using overlapped IO requires to call
CreateNamedPipe(name, FILE_FLAG_OVERLAPPED, ...) so the OS must know
about overlapped IO on pipe creation.  That disqualifies anonymous pipes
for overlapped operation.  Too bad.  Named pipes can be bidirectional.
I guess it would simplify Cygwin enormously, if we could use named pipes
for pseudo ttys, signals(?), etc.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                      
Red Hat, Inc.

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