Open sockets non-overlapped?
Tue Jun 13 08:21:00 GMT 2006
On Jun 12 21:43, Lev Bishop wrote:
> It doesn't make it any less useful to native processes _as a socket
> handle_ but it does make a difference when the native processes use it
> _as a file handle_. As you know, the semantics of WriteFile() et al
> change completely depending on whether they get an overlapped handle
> or not (eg the LPOVERLAPPED parameter either _must_ be null or _must
> not_ be null [...]
Uh, yes, right. I can see the potential benefit. Is the behaviour
of ReadFile/WriteFile with overlapping sockets the same? Did you try
to write a native testcase (not cygwin) to test this and find out
what happens when no Cygwin is involved at all? This might give us
some interesting clews.
> Hmph. It works for me. Must be some difference in our configurations,
> windows versions, etc. I note that msdn warns that using socket
> handles as file handles is an optional feature and not all providers
> support it. I guess the provider must be both a Winsock provider and
> also a file-system driver in order to make this work. Maybe you have
> some LSPs on your machine or something?
XP SP2 w/ official updates, plus SFU NFS and a bluetooth stack.
Standard AF_INET sockets should usually work, though. There's nothing
but standard file/socket types involved in this example. After all,
I'm running `cmd /c dir' on my NTFS home dir and the AF_INET socket
provider is Microsoft's own. Maybe I'm naive, but I would assume that
this problem would only happen with 3PPs.
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Project Co-Leader cygwin AT cygwin DOT com
More information about the Cygwin-patches