How to make eclipse PTP to support c++ code completion and open declaration?

I know that the C++ bindings in MPI deprecated since version 2.2 (http://ift.tt/1Ir8jeJ), but still I want to use C++ with MPI. I set up eclipse PTP, created an MPI C++ project by following the wizard, but I found that code completion and open declaration don't work, and these two functions work in a pure C++ project and C MPI project.

I noticed that there is a header file called mpicxx.h which wrapped all MPI C functions to a namespace called MPI, so I doubt this is an indexer issue. I took an hour to googling and trying to find a solution, but no luck. Can anyone tell how to make these two functions work in a ptp C++ project?

Update: next day,these two functions worked.
I am not sure which operation fixed these problem.Best guessing is eclipse restarting.Yesterday,to ensure problem do exist,I recreated new simple c++ project/c mpi project/c++ mpi project twice,ensured these two functions don't work in c++ mpi project only.I can't remember whether I restart eclipse or not during these operations.Maybe not.This is unreproducible problem,so I can't report it as a bug.I do found that eclipse is not stable on ubuntu multiple times.