/*D
   MPI_Ibarrier - Notifies the process that it has reached the barrier and returns immediately

Synopsis:
.vb
int MPI_Ibarrier(MPI_Comm comm, MPI_Request *request)
.ve

Input Parameters:
. comm - communicator (handle)

Output Parameters:
. request - communication request (handle)

Notes:
MPI_Ibarrier is a nonblocking version of MPI_barrier. By calling MPI_Ibarrier,
a process notifies that it has reached the barrier. The call returns
immediately, independent of whether other processes have called MPI_Ibarrier.
The usual barrier semantics are enforced at the corresponding completion
operation (test or wait), which in the intra-communicator case will complete
only after all other processes in the communicator have called MPI_Ibarrier. In
the intercommunicator case, it will complete when all processes in the remote
group have called MPI_Ibarrier.

.N ThreadSafe

.N Fortran

.N Errors
.N MPI_SUCCESS
.N MPI_ERR_ARG
.N MPI_ERR_COMM
.N MPI_ERR_OTHER

D*/

