def gen_rootcint_hook(self, node):
    if not self.env['GENROOTCINT_DICTNAME']:
        # project with *no* rootcint target...
        return
    source = node.name
    out_node_dir = self.path.get_bld().make_node(
        "_rootcint_dicts").make_node(
        self.env['GENROOTCINT_DICTNAME']
        )

    bld_node = out_node_dir
    out_node = bld_node.make_node(source.replace(".h",".cxx"))
    tsk = self.create_task('gen_rootcint', node, [out_node,])
    self.source += tsk.outputs
    #merge_dsomap_hook(self, dsomap_node).set_run_after(tsk)
Bind the .h file extension to the creation of a gen_rootcint instance
dataset/ETHPy150Open hwaf/hwaf/py-hwaftools/find_root.py/gen_rootcint_hook