[dpdk-dev] [PATCH v5 4/8] eal: sys/queue.h implementation for windows

[Thomas Monjalon]

26/03/2019 23:34, Jeff Shaw:
> On Tue, Mar 26, 2019 at 11:23:50PM +0100, Thomas Monjalon wrote:
> > 26/03/2019 22:54, Jeff Shaw:
> > > On Tue, Mar 26, 2019 at 10:47:54PM +0100, Thomas Monjalon wrote:
> > > > 26/03/2019 22:14, Jeff Shaw:
> > > > > On Tue, Mar 26, 2019 at 09:52:57PM +0100, Thomas Monjalon wrote:
> > > > > > Even better would be to get it as a dependency outside of DPDK.
> > > > > > Where this code come from?
> > > > > > How other projects on Windows get it?
> > > > > 
> > > > > It comes from FreeBSD 12.0, specifically
> > > > >   https://github.com/freebsd/freebsd/blob/releng/12.0/sys/sys/queue.h
> > > > > 
> > > > > It has been modified such that only the parts used by DPDK (i.e. TAILQ) are
> > > > > implemented. The other stuff has been deleted. Windows does not have sys/queue.h,
> > > > > so we reproduce it here.
> > > > > 
> > > > > Would it better to have this as a dependency outside of DPDK? I think pulling a file
> > > > > from the internet and applying a patch (where we'd have to maintain a patch file
> > > > > inside of DPDK's repo anyway) would be overkill when we just need a few lines of
> > > > > code that will change very infrequently.
> > > > 
> > > > We already try to get the libbsd dependency on Linux.
> > > > Why not mandate libbsd for Windows?
> > > > It has this header file and a lot more:
> > > > 	https://gitlab.freedesktop.org/libbsd/libbsd/blob/master/include/bsd/sys/queue.h
> > > > 
> > > > Relying on libbsd may avoid copying other files for Windows port.
> > > 
> > > I like that idea, though it doesn't look like libbsd builds on Windows, do you
> > > know of a Windows version or one that doesn't depend on autotools to build?
> > 
> > It seems libbsd is not packaged for Windows.
> > May be worth to ask opinions to libbsd maintainers.
> > 
> > Please could you list which other headers are required for the Windows port?
> 
> For helloworld the only one is sys/queue.h.
> 
> The dpdk-draft-windows repo has at least these (non-empty) ones:
>   dirent.h
>   getopt.h
>   net/ethernet.h
>   net/socket.h
>   netinet/in.h
>   netinet/tcp.h
>   pthread.h
>   rand48.h
>   sched.h
>   sys/_iovec.h
>   sys/_sockaddr_storage.h
>   sys/_termios.h
>   sys/_types.h
>   sys/cdefs.h
>   sys/mman.h
>   sys/netbsd/queue.h
>   sys/queue.h
>   sys/sysctl.h
>   syslog.h
>   termios.h
>   unistd.h
> 
> There will likely be more as more libraries are identified with dependencies on UNIX-like
> headers.

I would like we find a good solution for these headers.
How other cross-platform projects are getting such dependencies?
Is Cygwin a solution?