Blocking Routines
•A blocking send returns only after the send buffer is safe for reuse.
•This can be synchronous.
•It can be asynchronous if buffering is used.
•A blocking receive returns only after the data has arrived fully and is ready to use.
•MPI_SEND (buf, count, type, dest, tag, comm, ierr)
•MPI_RECV (buf, count, type, src, tag, comm, status, ierr)