Objective-C++ visibility question

I have linked a library with my program. It works fine. The only problem is that there visibility errors/warnings (thousands of them).

They are all of the form:

newlib::method() has different visibility (default) in newlib.a and (hidden) in AppDelegate.o

It is always with开发者_如何学C AppDelegate.o. I have tried to set the visibility for both the library and the main app in several ways: the visibility checkmark in XCode, and -fvisibility. Non seem to have worked. Is there somethin special about AppDelegate.mm?

The XCode system for dealing with errors is not very bright.

I had a function called Error() and XCode treated every warning about this function as an error.