[vtk-developers] Visibility flags and C

[Marcus D. Hanwell]

On Wed, Aug 15, 2012 at 4:32 PM, David Gobbi <david.gobbi at gmail.com> wrote:
> On Wed, Aug 15, 2012 at 2:11 PM, Marcus D. Hanwell
> <marcus.hanwell at kitware.com> wrote:
>>
>> I think we are doing this for all VTK libraries that are built shared,
>> and I didn't account for C only libraries. Is there a good way to tell
>> if a target is a C only library from the CMake level for things like
>> this?
>
> When BUILD_SHARED_LIBS is ON, then it is done for all libraries,
> whether the individual libraries are built shared or not.  Not to say
> that's wrong... in fact I think that it's the right way to go.  The
> flags are added around line 467 in vtkModuleMacros.cmake:

For all libraries in vtk_module_library, which are controlled by
BUILD_SHARED_LIBS. So when the libraries are built static it will not
be passed.
>
> if (BUILD_SHARED_LIBS)
>   add_compiler_export_flags(my_abi_flags)
>   ...
>
> But the main issue is that the same flags are added for both C and
> C++, even though -fvisibility-inlines-hidden is a C++-only flag.
>
I think we could use the LINKER_LANGUAGE property Dave Cole pointed
out, and filter appropriately. VTK is mainly a C++ toolkit, so when I
added this code I assumed all libraries using vtk_module_library would
be C++ libraries - are you sure you wouldn't be better just using
vtk_add_library? They are expected to be VTK C++ modules when that
function is called.

Marcus