[ovs-dev] [PATCH] configure: Properly handle case where libunwind.h is not available.

Yi-Hung Wei yihung.wei at gmail.com
Tue Oct 15 23:49:33 UTC 2019


On Tue, Oct 15, 2019 at 3:25 PM Ben Pfaff <blp at ovn.org> wrote:
>
> On Tue, Oct 15, 2019 at 02:30:48PM -0700, Yi-Hung Wei wrote:
> > It is possible that user install libunwind but not libunwind-devel,
> > and it will run into a compilation error.  So check the existence
> > of the header file instead of the library.
> >
> > Fixes: e2ed6fbeb18c ("fatal-signal: Catch SIGSEGV and print backtrace.")
> > Signed-off-by: Yi-Hung Wei <yihung.wei at gmail.com>
> > ---
> >  m4/openvswitch.m4 | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/m4/openvswitch.m4 b/m4/openvswitch.m4
> > index 79e0be5a33dd..da7119951484 100644
> > --- a/m4/openvswitch.m4
> > +++ b/m4/openvswitch.m4
> > @@ -640,7 +640,7 @@ AC_DEFUN([OVS_CHECK_UNBOUND],
> >
> >  dnl Checks for libunwind.
> >  AC_DEFUN([OVS_CHECK_UNWIND],
> > -  [AC_CHECK_LIB(unwind, unw_backtrace, [HAVE_UNWIND=yes], [HAVE_UNWIND=no])
> > +  [AC_CHECK_HEADERS([libunwind.h], [HAVE_UNWIND=yes], [HAVE_UNWIND=no])
>
> It might be wise to check for both, e.g.:
>
> AC_CHECK_LIB([unwind], [unw_backtrace],
>   [AC_CHECK_HEADERS([libunwind.h], [HAVE_UNWIND=yes], [HAVE_UNWIND=no])],
>   [HAVE_UNWIND=no])
>

Hi Ben,

In most distros, libunwind-devel (or libunwind-dev) depends on
libunwind.  Is it necessary for us to check both?

Thanks,

-Yi-Hung


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