text: /* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
  /*
   *  (C) 2017 by Argonne National Laboratory.
   *      See COPYRIGHT in top-level directory.
   */
  
  #include "mpiimpl.h"
  
  #undef FUNCNAME
  #define FUNCNAME MPIR_Ibarrier_sched_inter_bcast
  #undef FCNAME
  #define FCNAME MPL_QUOTE(FUNCNAME)
  int MPIR_Ibarrier_sched_inter_bcast(MPIR_Comm * comm_ptr, MPIR_Sched_t s)
  {
      int mpi_errno = MPI_SUCCESS;
      int rank, root;
      MPIR_SCHED_CHKPMEM_DECL(1);
      char *buf = NULL;
  
      MPIR_Assert(comm_ptr->comm_kind == MPIR_COMM_KIND__INTERCOMM);
  
      rank = comm_ptr->rank;
  
      /* Get the local intracommunicator */
      if (!comm_ptr->local_comm) {
          mpi_errno = MPII_Setup_intercomm_localcomm(comm_ptr);
          if (mpi_errno)
              MPIR_ERR_POP(mpi_errno);
      }
  
      /* do a barrier on the local intracommunicator */
      if (comm_ptr->local_size != 1) {
          mpi_errno = MPIR_Ibarrier_sched(comm_ptr->local_comm, s);
          if (mpi_errno)
              MPIR_ERR_POP(mpi_errno);
          MPIR_SCHED_BARRIER(s);
      }
      /* rank 0 on each group does an intercommunicator broadcast to the
       * remote group to indicate that all processes in the local group
       * have reached the barrier. We do a 1-byte bcast because a 0-byte
       * bcast will just return without doing anything. */
  
      MPIR_SCHED_CHKPMEM_MALLOC(buf, char *, 1, mpi_errno, "bcast buf", MPL_MEM_BUFFER);
      buf[0] = 'D';       /* avoid valgrind warnings */
  
      /* first broadcast from left to right group, then from right to
       * left group */
      if (comm_ptr->is_low_group) {
          root = (rank == 0) ? MPI_ROOT : MPI_PROC_NULL;
          mpi_errno = MPIR_Ibcast_sched(buf, 1, MPI_BYTE, root, comm_ptr, s);
          if (mpi_errno)
              MPIR_ERR_POP(mpi_errno);
  
          MPIR_SCHED_BARRIER(s);
  
          /* receive bcast from right */
          root = 0;
          mpi_errno = MPIR_Ibcast_sched(buf, 1, MPI_BYTE, root, comm_ptr, s);
          if (mpi_errno)
              MPIR_ERR_POP(mpi_errno);
      } else {
          /* receive bcast from left */
          root = 0;
          mpi_errno = MPIR_Ibcast_sched(buf, 1, MPI_BYTE, root, comm_ptr, s);
          if (mpi_errno)
              MPIR_ERR_POP(mpi_errno);
  
          MPIR_SCHED_BARRIER(s);
  
          /* bcast to left */
          root = (rank == 0) ? MPI_ROOT : MPI_PROC_NULL;
          mpi_errno = MPIR_Ibcast_sched(buf, 1, MPI_BYTE, root, comm_ptr, s);
          if (mpi_errno)
              MPIR_ERR_POP(mpi_errno);
      }
  
      MPIR_SCHED_CHKPMEM_COMMIT(s);
    fn_exit:
      return mpi_errno;
    fn_fail:
      MPIR_SCHED_CHKPMEM_REAP(s);
      goto fn_exit;
  }
  