Function starpu_create_sync_task 

pub unsafe extern "C" fn starpu_create_sync_task(
    sync_tag: starpu_tag_t,
    ndeps: c_uint,
    deps: *mut starpu_tag_t,
    callback: Option<unsafe extern "C" fn(arg1: *mut c_void)>,
    callback_arg: *mut c_void,
)

Create and submit an empty task that unlocks a tag once all its dependencies are fulfilled. See \ref SynchronizationTasks for more details.