doc: better document `--shared` build

[refack]

• Version: *
• Platform: *
• Subsystem: build,doc

./configure --shared / vcbuild shared should be better documented.

1. How to build
2. How to use
3. Support level

[addaleax]

If I may make the suggestion, we should also test it in some way if possible.

[refack]

If I may make the suggestion, we should also test it in some way if possible.

If we decide to support, maybe it should be deprecated?

[edit]
I'm just playing devil's advocate, it think it's an important meta-feature. But without CI testing it has rotted...
@electron @nwjs @nodejs/electron-installer @nodejs/build

[gibfahn]

cc/ @mhdawson, @a-roberts (and maybe @sam-github) who were looking at this.

[mhdawson]

I've had it on our internal backlog to push this forward, we've just not gotten started on it yet. My starting goals are:

1. define set of tests to validate shared library works
2. add tests to ci, ideally in the regression runs
3. look at how we can better package/delivery, ideally as part of the binaries we already ship. Challenge on this front is not increasing the package size so we may need to look at moving to the node binary being a launcher that uses the shared library, this is what Java does.

[mhdawson]

And I'm firmly on the side that we need to improve not remove. It is used by electron and we also have internal products that need it.

[mhdawson]

The person(s) on our team who worked on this in the past have moved on to a different project. My next step is to schedule some handover with them but then it will still be a matter on finding time to move it forward.

[refack]

add tests to ci, ideally in the regression runs

#13078 tried to get cctest to link against the shared lib. Could ideally become said launcher so we can run the JS suite against it.

[refack]

#13078 tried to get cctest to link against the shared lib. Could ideally become said launcher so we can run the JS suite against it.

Alternatively create something like d8 that will both serve as a test harness and an embedding example.

[mhdawson]

@gibfahn can you post the launcher code that we already have for testing the shared library ? I've not had time to get back to this and it would at least be something we can discuss here in terms of moving forward on the testing.

[mhdawson]

Seein #15195 maybe we should add a job that simply compiles the shared library as a first step towards fully testing it.