[mythtv-commits] Ticket #9426: MacOS X symbols missing

[MythTV]

#9426: MacOS X symbols missing
-------------------------+----------------------------
 Reporter:  nigel        |          Owner:  stuarta
     Type:  Bug Report   |         Status:  closed
 Priority:  minor        |      Milestone:  0.25
Component:  Ports - OSX  |        Version:  Trunk Head
 Severity:  medium       |     Resolution:  Fixed
 Keywords:               |  Ticket locked:  0
-------------------------+----------------------------

Comment (by Dave Morrison <dave@…>):

 Replying to [comment:12 stuarta]:
 > I'm not seeing this on Snow Leopard with the current XCode toolset.
 > What is it you are running on?

 10.5.8 with gcc 4.0.1.  I see the following in the development notes for
 gcc 4.2:

 C++ visibility handling has been overhauled.

 Restricted visiblity is propagated from classes to members, from functions
 to local statics, and from templates and template arguments to
 instantiations, unless the latter has explicitly declared visibility.

 So if I whip up a little test case, "visible.cpp":


 {{{
 #define MPUBLIC __attribute__((visibility("default")))

 struct MPUBLIC outer
 {
   outer() {}
   struct inner
   {
     inner() {}
   } in;
 };


 float g()
 {
   outer o;
 }
 }}}

 and do this:


 {{{
 $ /usr/bin/g++-4.0 -dynamiclib -o visible.so -fvisibility=hidden
 visible.cpp && nm visible.so | c++filt | grep inner
 00000f80 t outer::inner::inner()
 }}}

 you see that the nested class isn't globally visible.  If I do this:

 {{{
 $ /usr/bin/g++-4.2 -dynamiclib -o visible.so -fvisibility=hidden
 visible.cpp && nm visible.so | c++filt | grep inner
 00000f80 T outer::inner::inner()
 }}}

 you can see that the nested class *is* globally visible.

 So, FWIW, I think it's due to differences in visibility handling between
 gcc 4.0 and 4.2.

 Unless I'm completely wrong, that is.

-- 
Ticket URL: <http://code.mythtv.org/trac/ticket/9426#comment:13>
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