Re: [Boost-users] questions about visibility/dlls under mingw

Subject: Re: [Boost-users] questions about visibility/dlls under mingw
From: John Maddock (jz.maddock_at_[hidden])
Date: 2018-11-20 21:16:18

> Note that in the test there is dll_polymorphic_derived2.  This exports 
> a couple of functions.  But it depends on dll_polymorphic_base and 
> imports some symbols from that.  In C++, the class derived2 inherits 
> from the class base.  So within the same module we're both exporting 
> and importing albeit different symbols.  The normal windows tests seem 
> to be fine with this.  I'll try to figure out what mingw does 
> differently.
>

To take a concrete example, in the failing 
"test_no_rtti_polymorphic_text_archive", both polymorphic_derived2.o and 
test_no_rtti.o are linked directly into the executable (no dll's 
involved), but in the former you are dllexport'ing the class and the 
latter dllimport'ing, and since it's all one big exectutable with no 
dll's the import/export is redundant and ideally you would be doing 
neither, but if you must mark them up, then it should be dllexport all 
the way.

John.

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