Visibility settings cause warnings when compiling for Release

[mhaylock]

When compiling our app for Release I get warnings like:

ld: warning: direct access in void boost::throw_exception<boost::gregorian::bad_month>
(boost::gregorian::bad_month const&) to global weak symbol typeinfo for 
boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::
gregorian::bad_month> > means the weak symbol cannot be overridden at runtime. This was 
likely caused by different translation units being compiled with different visibility 
settings.

I can see this occurs because "Symbols Hidden by Default" is YES in a Release build. A bit of Googling suggests that boost should have been compiled with -fvisibility=hidden -fvisibility-inlines-hidden, which was the case until this commit.

Would the fix be as simple as reintroducing these compilation options, or do they cause other problems?

[danoli3]

Yeah definitely re-introducing that line. Thanks for this report.

[mhaylock]

No problem, although (just incase you didn't already mean this) to clarify: it should be re-introduced for both iphone and iphonesim :)

[danoli3]

Fixed in new releases for 1.59.0 and master.

[mhaylock]

@danoli3 it's not clear to me why, but trying this new version I get the visibility warnings in Debug now, even if I do change "Symbols Hidden by Default" to YES to DEBUG.

Perhaps I've lead you astray with my suggestion here?

[danoli3]

I found this: http://stackoverflow.com/questions/19190458/visibility-linker-warnings-when-compiling-ios-app-that-uses-boost

Interesting might be related to clang++ vs clang.............weird. Want to try and edit the build script yourself to clang rather than clang++ here: https://github.com/danoli3/ofxiOSBoost/blob/master/scripts/build-libc%2B%2B.sh#L29

See if that gets rid of the warnings? After re-building

[mhaylock]

@danoli3 I did try using clang (saw that myself) with no luck.

I've observed that no matter what the setting for "Symbols Hidden by Default" (including making sure it's consistent in the Pods project as well) it never passes -fvisibility=hidden when compiling while in DEBUG mode. Seems like an Xcode bug, but perhaps I'm missing something…

[danoli3]

Yeah throw Apple a report: https://bugreport.apple.com

Let me know what their engineers say.