/*D
   MPI_Barrier - Blocks until all processes in the communicator have reached this routine.

Synopsis:
.vb
int MPI_Barrier(MPI_Comm comm)
.ve

Input Parameters:
. comm - communicator (handle)

Notes:
Blocks the caller until all processes in the communicator have called it;
that is, the call returns at any process only after all members of the
communicator have entered the call.

.N ThreadSafe

.N Fortran

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

D*/

