[cfe-dev] Visibility in libc++

[Nico Rieck]

Hi,

libc++ applies visibility default to all public types and functions, 
including templates. On Windows these visibility macros expand to 
dllexport/import which makes no sense for templates (If someone uses a 
vector<int> it is then expected that something else is exporting such a 
specialization).

Before I send a patch I have two questions:

1. AFAICS the visibility attributes were added for cases when the
    libc++ headers are included inside of visibility scopes. Could
    someone clarify why visibility is needed on header-only templates?

2. If these are indeed needed, then templates require a different macro
    that only expands to visibility. I currently use
    _LIBCPP_(TYPE|FUNC)_PUBLIC for both, and _LIBCPP_(TYPE|FUNC)_VIS for
    only visibility. Thoughts?

-Nico