Meson, add build options to CMake subproject

Question

Basically I have a cmake subproject as part of my meson.build, I would like to be able to add -DSOMEDEF=4 to the build of that subproject.

user_1202172 · Answer

You should probably use yield in the meson.options file.

Add the option in your top project:

option('somedef',
    type : 'combo',
    choices : [
      '1',
      '2',
      '4'
      ],
    description : 'Some def')

Add the same option in your subproject, but with the yield set to true:

option('somedef',
    type : 'combo',
    choices : [
      '1',
      '2',
      '4'
      ],
    yield : true,
    description : 'Some def')

This way the option will be taken from the top project.

In your meson.build add something like (top project):

somedef = get_option('somedef')

and in the subproject:

somedef = get_option('somedef')
if somedef==4
  flags += ['-DSOMEDEF=4']

  # etc...
endif