[Octave-bug-tracker] [bug #61711] Test errors for sorting NaN values on Windows with visibility flags

[Markus Mützel]

Update of bug #61711 (project octave):

                  Status:             In Progress => Patch Submitted        

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Follow-up Comment #10:

The classes exported by the standard library are a bit different conceptually
from what we do with the Array<T> template class.
In the standard library, instead of exporting specialized template classes
directly, they do the "specialization" in child classes.
E.g., for the `std::basic_string<T>` template class, instead of exporting the
specializations in `std::basic_string<char>`, they create a child class
`std::string` and export that child class with any "specializations" (i.e.,
overloaded methods).

In liboctave and liboctinterp, we'd like to export things like `Array<double>`
including any specializations directly (without an "indirection" through a
child class).

That means the same concepts that are used for exporting template classes in
the standard library cannot be applied directly to Octave.
However, it is still possible to imitate some of the ideas to our use case.

The attached patch is an attempt to mimic the more fine-grained visibility
flags that they are using in libcxx and apply that idea to our template
classes.
Since we are building a couple of different libraries that link to each other,
that results in a whole lot of API flags that could potentially be used. Not
all of them are used in all libraries currently. But I figured it would make
sense to nevertheless define all of them for symmetry reasons (see the changes
in `oct-conf-post-public.in.h`).

Judging from how they define these flags, MSVC and MinGW compilers seem to
require different combinations of attributes. Afaict, currently no one is
building Octave with MSVC. But I kept the distinction they are making
anyways.

Is there a way to not having to repeat these definitions almost identically
several times? E.g., can a pre-processor macro be used to create several
pre-processor definitions?


(file #53931)

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Additional Item Attachment:

File name: bug61711-template-visibility.patch Size:54 KB
   
<https://file.savannah.gnu.org/file/bug61711-template-visibility.patch?file_id=53931>



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