nupic.core can be built as shared lib

[oxtopus]

Ideally, nupic.core build optionally accepts -DBUILD_SHARED_LIBS=true CLI option to build libnupic_core.so (on linux systems, for example) as a shared object.

[rhyolight]

See discussion about Windows DLL building at https://github.com/numenta/nupic.core/pull/184#issuecomment-57468663.

[rcrowder]

Ahmed and I was discussing this in a Gitter room last night. He's made an initial stab at this and got it built as a DLL and linked to the helloregion example. All looking good on windows.

DLL Feature branch https://github.com/kandeel/nupic.core/tree/dll Build histories https://ci.appveyor.com/project/kandeel/nupic-core/history Packaging https://ci.appveyor.com/project/kandeel/nupic-core-393/build/artifacts

One blocking question is how we handle labeling of exportable Classes and functions. Our discussion revolved around class Visibility http://gcc.gnu.org/wiki/Visibility By placing -fvisibility=hidden on all GCC compiles to make everything hidden from export by default. A pre-processor definition can then decorate at the class declaration level to export an entire class or drill down and specify individually class functions to export. All that came from reading http://stackoverflow.com/questions/2839504/is-there-a-def-file-equivalent-on-linux-for-controlling-exported-function-names?rq=1

Definitely available as a GCC option in 4.3.3, Travis is using 4.6.3 at the moment. Clang and OSX look like it can handle that option too https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/DynamicLibraries/100-Articles/DynamicLibraryDesignGuidelines.html

For the time being Ahmed has chosen NUPIC_EXPORTS for the pre-processor definition e.g. https://github.com/kandeel/nupic.core/commit/c4dcafef747acdb6bdc12756da0cf5a178815108

Is this ok to use, or rather something else?

[rhyolight]

@rcrowder said:

For the time being Ahmed has chosen NUPIC_EXPORTS for the pre-processor definition e.g. kandeel@c4dcafe

Is this ok to use, or rather something else?

Any comments, @scottpurdy / @breznak / @oxtopus ?

[scottpurdy]

There is an export macro NTA_EXPORT defined in src/main/types/Types.h

[rcrowder]

Excellent, thank you Scott. I believe Ahmed has already made the change in the windows branch to use this define now.

[rhyolight]

@oxtopus You tagged this as "in progress"... still true?

[rhyolight]

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[breznak]

still valid, only static .a lib is generated.