[PATCH wayland v2 1/4] wayland-util: do not export the wl_map_* API

[Pekka Paalanen]

On Tue, 14 Mar 2017 15:52:20 +0000
Emil Velikov <emil.l.velikov at gmail.com> wrote:

> On 14 March 2017 at 11:31, Pekka Paalanen <ppaalanen at gmail.com> wrote:
> > On Tue, 21 Feb 2017 16:14:26 +0000
> > Emil Velikov <emil.l.velikov at gmail.com> wrote:
> >  
> >> From: Emil Velikov <emil.velikov at collabora.com>
> >>
> >> Used only internally and explicitly marked as such with commit
> >> cf04b0a18f2 ("Move private definitions and prototypes to new
> >> zwayland-private.h")
> >>
> >> Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
> >> ---
> >>  src/wayland-util.c | 18 +++++++++---------
> >>  1 file changed, 9 insertions(+), 9 deletions(-)  
> >
> > Hi,
> >
> > R-b me and pushed:
> >    9b78be6..654dee8  master -> master
> >
> >
> > Let's see if anyone screams and forces us to revert. These have not
> > been in public headers even in 1.0 release.
> >  
> Thanks and let's hope we don't have to revert it.
> 
> > I verified with 'nm -g --defined-only' that this patch indeed does stop
> > exporting the symbols.
> >  
> I think you want `nm -CD --defined-only' here, since -g produces "no
> symbols" even for libraries such as libGL.so.
> Strictly speaking D is not needed, since it demangles any C++ symbols.

Hmm, yes... still the output was completely what I was expecting.

$ nm -g --defined-only $WLD/lib/libwayland-*.so > newsyms.txt
$ nm -CD --defined-only $WLD/lib/libwayland-*.so > newsyms2.txt

The results are identical. Why is that, and why is it not that with
libGL.so?

I feel like I'm missing some shared object basics here.

If I am to trust and understand
http://stackoverflow.com/questions/15345543/when-to-use-dynamic-option-in-nm

it seems that I would actually want -g --defined-only because I'm
interested only in symbols usable from outside. In addition I would
want -D to look at the dynamic table which will be used by the runtime
linker. So actually I'd want all those options?

Which means I was actually comparing the static linking tables of a...
shared object file... which doesn't make any sense?

That leaves a fun question of what kind of symbol would be defined, in
the dynamic table, but not exported. Perhaps a weak function with an
implementation but allowed to be overridden by another provider
exporting the same?

Just for fun:

$ diff -u <(nm -DC --defined-only /usr/lib/libGL.so.1.2.0 ) <( nm -gDC --defined-only /usr/lib/libGL.so.1.2.0 )
--- /dev/fd/63	2017-03-15 12:19:45.931004715 +0200
+++ /dev/fd/62	2017-03-15 12:19:45.931004715 +0200
@@ -1,6 +1,3 @@
-0000000000272a88 b __bss_start
-0000000000272a88 d _edata
-00000000002735a8 b _end
 0000000000059054 T _fini
 0000000000017dd8 T _init
 0000000000052da0 T glAccum


I'll try to remember to use 'nm -gDC --defined-only' in the future,
correct?

> > I haven't looked at the other patches yet, this seemed like something
> > to get in early in a release cycle.
> >
> > I still can't make my mind about the extra .so introduced in patch 3.
> >  
> Anything I can do to sway you to the dark side ?
> If Linux distribution is one of the core concerns I won't mind sending
> them a patch or two.

That's the thing, I can't seem to form even questions about it. I
suppose I just really don't care as it is.


Thanks,
pq
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