[cmake-developers] Using CMake generated ninja file as a subninja file

[Ben Boeckel]

On Wed, Jan 06, 2016 at 19:26:11 +0100, Nicolas Desprès wrote:
> Is that variable already available or a name suggestion? I cannot find any
> reference to it neither in the source nor in the documentation.

It's a suggestion.

> This is acceptable for me since I have a custom generator that would write
> the top build.ninja containing "subninja sub/build.ninja". The end-user is
> supposed to run ninja from the top directory not from the top/sub/
> directory.

It looks like subclassing cmLocalNinjaGenerator to override some
path-related bits and it should work (though it has changed enough with
cmState that I can't tell what exactly without doing more digging).

The hardest problem is going to be with testing. Every generate step
will also have to dump a build.ninja file out so that it can be properly
tested.

Brad is back later this week and may have other ideas too.

--Ben