[ovs-dev] [PATCH] use AX_PTHREAD to detect pthreads

Ben Pfaff blp at nicira.com
Sat Apr 18 04:41:19 UTC 2015


On Sat, Apr 18, 2015 at 01:28:21AM +0800, Kevin Lo wrote:
> On Fri, Apr 17, 2015 at 09:17:46AM -0700, Ben Pfaff wrote:
> > 
> > On Fri, Apr 17, 2015 at 02:45:32PM +0800, Kevin Lo wrote:
> > > On Wed, Apr 15, 2015 at 05:50:42PM -0700, Ben Pfaff wrote:
> > > > 
> > > > On Wed, Apr 15, 2015 at 07:52:24AM -0700, Gurucharan Shetty wrote:
> > > > > >
> > > > > > I am also concerned that it this will break the Windows build.
> > > > > > Currently Windows uses some Windows-only code in m4/openvswitch.m4,
> > > > > > which requires Win32 builders to specify --with-pthread=<dir> on the
> > > > > > configure command line.  Ideally, we would want Windows builds to work
> > > > > > the same as other builds.  Maybe that would mean that Windows builders
> > > > > > should specify the PTHREAD_* variables on the configure command line,
> > > > > > instead of --with-pthread, or that the OVS pthread-win32 support should
> > > > > > move from OVS_CHECK_WIN32 to somewhere around the new invocation of
> > > > > > AX_PTHREAD.  Either way, I think that this will require some change to
> > > > > > what this patch does (and possibly an update to INSTALL.Windows.md)
> > > > > > before it can go in.  I'm CCing Guru, who knows the Windows build, to
> > > > > > get his opinion.
> > > > > 
> > > > > commit 94887cf4caa74bfb5 added the support for pthreads check for Windows.
> > > > > As one can see in that commit, we have very specific Windows related
> > > > > includes, ldflags, libs that we need added. This is mainly because
> > > > > pthreads on Windows is downloadable and installed in any directory. I
> > > > > do not know what is a good portable solution here if we need to make
> > > > > Windows related changes again there.
> > > > > 
> > > > > One concern that I have in changing '--with-pthread' for Windows means
> > > > > that the auto builds at different places will also need changing.
> > > > > Unless the benefits look good, I would like to avoid making that
> > > > > change.
> > > > 
> > > > I think that this is pretty close to working already, actually.  The
> > > > proposed AX_PTHREAD allows previously set shell variables PTHREAD_CFLAGS
> > > > and PTHREAD_LIBS to control how pthread compiling and linking should
> > > > work.  I think that OVS_CHECK_WIN32 could simply set these variables:
> > > > PTHREAD_CFLAGS to the -I option and PTHREAD_LIBS to the -L and -l
> > > > options.
> > > > 
> > > > We'd want to ensure that OVS_CHECK_WIN32 gets called before AX_PTHREAD.
> > > > I think we can add AC_BEFORE([$0], [AX_PTHREAD]) to OVS_CHECK_WIN32 to
> > > > ensure that.
> > > 
> > > I know some of you are concerned about it will break build on Windows.
> > > The diff below fixes pthread linking on FreeBSD.
> > > Tested on Linux, NetBSD, and FreeBSD.
> > 
> > Does the following even simpler change also fix the problem on BSD?
> 
> Indeed.  I must have more coffee :(  Sorry for the noise.

Will you submit this diff with an updated commit message, then?  I'm
happy that we arrived at such a straightforward solution!

> > diff --git a/configure.ac b/configure.ac
> > index 8af5ef0..b100c80 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -81,7 +81,7 @@ AC_SUBST([LT_AGE])
> >  AC_SEARCH_LIBS([pow], [m])
> >  AC_SEARCH_LIBS([clock_gettime], [rt])
> >  AC_SEARCH_LIBS([timer_create], [rt])
> > -AC_SEARCH_LIBS([pthread_sigmask], [pthread])
> > +AC_SEARCH_LIBS([pthread_create], [pthread])
> >  AC_FUNC_STRERROR_R
> >  
> >  OVS_CHECK_ESX



More information about the dev mailing list