[libvirt] [PATCH] fix WIN64 compatibility bug in external EventImpl API

[David Lively]

On Wed, 2008-11-19 at 18:33 +0000, Daniel P. Berrange wrote:
> On Wed, Nov 19, 2008 at 01:28:23PM -0500, David Lively wrote:
> > On Wed, 2008-11-19 at 16:49 +0000, Daniel P. Berrange wrote:
> > > On Wed, Nov 19, 2008 at 11:41:43AM -0500, David Lively wrote:
> > > > While starting to think about Windows compability, I realized the newly
> > > > exposed API for registering an external EventImpl is not adequate.
> > > > Currently it's assuming 32-bit unix fds.  But Windows uses a pointer
> > > > (HANDLE) here.  So we need to generalize this interface so it can be
> > > > implemented for 64-bit Windows.  The attached patch does this.  (I'm
> > > > sure it conflicts with work Dan B is doing, so I'm hoping he'll just
> > > > incorporate this into his changes.)
> > > 
> > > I'm not sure whether this is actually required. We're using gnulib for
> > > socket stuff, and that wraps the Winsock socket() call so that it returns
> > > a real file descriptor rather than a socket handle. It does this calling
> > > _open_osfhandle which appears to be declared to accept a 'long' and return
> > > an 'int' - at least in MinGW headers.
> > 
> > That means that the Windows application using libvirt must use gnulib as
> > well.  If the Windows version of libvirt actually exports the gnulib
> > bindings and headers, then I guess that's not a problem.  But does it
> > export gnulib?
> 
> No, the gnulib stuff is internal only - we don't force any apps to also
> use gnulib.
> 
> It does however mean we should document that the 'fd' arg of the
> the  virEventAddHandle callback is an file handle, and not a socket
> handle on Win32, so apps are clear on what to expect.

Does Windows support integer file handles?  Or are they a winsock
concept - in which case we're assuming the app uses winsock, right?

[Sorry - I'm not trying to be thick -- I'm not a Windows guy at all.
But I have hazy memories of winsock not being "standard" WIN32 ...]

Dave