Re: [gtk-vnc-devel] [PATCH 3/4] Use Gnulib ioctl instead of ioctlsocket

["Daniel P. Berrange" <berrange redhat com>]

On Wed, Oct 29, 2008 at 03:07:08PM +0000, Richard W.M. Jones wrote:
> 
> This patch isn't necessary for Windows itself, but is important for
> Wine.  Wine apparently contains a bug where calls to ioctlsocket fail
> because it tries to interpret the first parameter as a handle.[1]
> 
> This calls Gnulib's replacement ioctl function instead.  It also
> rearranges the code so that the normal Unix case is first, and the
> Windows case second.  Also it uses WIN32 instead of __MINGW32__ as
> explained in patch 1/4.
> 
> Rich.
> 
> [1] Actually, I'm not totally sure this analysis is correct -- it's
> very hard to follow what the code is doing and what it's supposed to
> be doing.  Furthermore the concept of file descriptor vs socket vs
> handle is very confused on Windows itself.  In any case, this patch is
> still necessary to run gvncviewer.exe under Wine.

The bug isn't actually in WINE. The issue is that on Windows a socket
handle is not the same as a file handle. Winsock's socket() API
gives you back a socket handle, so using ioctlsocket() would be correct.
We're using GNULIB though, and this wraps Winsock's socket() API so
that it gives us back a true file handle as per POSIX. We were then
passing the file handle into ioctlsocket() which expects a socket
handle. Anyway enough rambling, your patch is doing the correct 
thing and calling ioctl() which gnulib does translation for.


Daniel
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