What does "without outcome" mean? Be aware that you cannot constrain too many edges; in particular, constrained edges may not cross each other. The reserve() call is not clever, the only thing it can do at that time is create an unnecessary reallocation.
If you struggle to apply the triangulation to your code, try with a minimal example (e.g. 5 vertices and 2 constrained edges). Draw it on paper and make sure the edge constraints make sense. Maybe also the existing triangulation example from the SDK helps you.
