[Boost-build] Boost on Xcode 3.2 generates visibility warnings

Subject: [Boost-build] Boost on Xcode 3.2 generates visibility warnings
From: Christopher Hunt (huntc_at_[hidden])
Date: 2009-08-30 08:11:15

Hi there,

Since Xcode 3.2 (the Xcode that ships with Snow Leopard) lots of "has  
different visibility" warnings surfaced when first building a project  
that uses boost 1_39.

I eventually discovered that Xcode's default behaviour for a target is  
to set GCC_INLINES_ARE_PRIVATE_EXTERN to YES. This conflicts with the  
way that the boost libraries are built. So I disabled it in my  
target's xcconfig file (you can also set it using the "Inline methods  
hidden" setting through the UI):

        GCC_INLINES_ARE_PRIVATE_EXTERN = NO

The warnings then disappear.

Interestingly the previous version of Xcode on Leopard didn't show  
these warnings despite the same default setting. Perhaps something was  
fixed in Xcode or gcc between gcc 4.0 and gcc 4.2.

Kind regards,
Christopher