[ovs-discuss] Problem with VLOG module init

Ben Pfaff blp at nicira.com
Wed Dec 5 19:50:13 UTC 2012


What's in config.status?

On Wed, Dec 05, 2012 at 11:46:17PM +0500, Ahmed Talha Khan wrote:
> Its Linux with kernel 2.6.35 on Fedora 14 x86_64 machine. And yes thats
> what I though too that only VLOG_DEFINE_THIS_MODULE should do the job as it
> creates and the actual module as well as the reference.
> 
> I see that it is defined like this
> 
> #define VLOG_DEFINE_THIS_MODULE(MODULE)                                 \
>         VLOG_DEFINE_MODULE(MODULE);                                     \
>         static struct vlog_module *const THIS_MODULE = &VLM_##MODULE
> 
> 
> The 2nd line to create a reference works as its not a compile issue. The
> linker cries which means that VLOG_DEFINE_MODULE(MODULE) failed to create
> the module in the linker section as given by
> 
> #define VLOG_DEFINE_MODULE(MODULE)                                      \
>         VLOG_DEFINE_MODULE__(MODULE)                                    \
>         extern struct vlog_module *vlog_module_ptr_##MODULE;            \
>         struct vlog_module *vlog_module_ptr_##MODULE                    \
>             __attribute__((section("vlog_modules"))) = &VLM_##MODULE
> 
> 
> Any ideas now what might have happened? Could be it some sort of a version
> mis-match for the GNU linker "ld"?
> 
> 
> 
> On Wed, Dec 5, 2012 at 8:35 PM, Ben Pfaff <blp at nicira.com> wrote:
> 
> > On Wed, Dec 05, 2012 at 12:29:51PM +0500, Ahmed Talha Khan wrote:
> > > I am trying to register one of my own modules for logging purpose but it
> > > does not seem to work.
> > >
> > > In my source file xyz.c included
> > >
> > > VLOG_DEFINE_THIS_MODULE(xyz);
> > >
> > > and then later in the file i use
> > >
> > > VLOG_INFO("some msg printed here")
> > >
> > > But when I run make, the linker cries:
> > >
> > > undefined reference to `VLM_xyz'.
> > >
> > > What am I missing here. Isnt this suppose to be a simple operation?
> >
> > Yes, all you should need is the VLOG_DEFINE_THIS_MODULE line.
> >
> > What kind of system are you using?
> >
> 
> 
> 
> -- 
> Regards,
> -Ahmed Talha Khan



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