Jeff Squyres wrote: > Pavan and I chatted on the phone this morning about > https://svn.open-mpi.org/trac/hwloc/ticket/4. > > The *easiest* solution for MPICH2 would be if they could > AC_CONFIG_SUBDIRS our configure script. However, this has the > condition that hwloc's configure could never fail -- e.g., it can't > call AC_MSG_ERROR. For unsupported platforms, it will need to still > succeed and build/install a token libhwloc.la. This libhwloc.a can > just return a graceful failure from hwloc_init() at run-time > indicating that it can't do anything on this platform. > > By default, I'm not comfortable with this. But I would be comfortable > with such a scheme if a non-default flag is passed to configure (e.g., > "--enable-always-build", or perhaps a better name). > > Would this be hard to do from the building side? I.e., I have not > looked in the C code much yet -- do we have much code that won't build > on unsupported platforms, or do we need a "generic / always fail" .c > file that is trivial/portable C, but always returns failures for all > hwloc API functions...?
>From my quick tests, if you try to build on a non-supported platform, you'll probably get a System object with 1 or N processors depending on whether sysconf is available. So building the topology looks ok. And you get -1 and ENOSYS if you try to bind. I am not sure how hard it'd be to avoid errors during configure. Are we sure PKG_* macros or other external things will never use AC_MSG_ERROR ? Brice
