+ MPI_Init(&argc, &argv);
+ MPI_Comm_size(MPI_COMM_WORLD, &size);
+ MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+ MPI_Comm_set_errhandler(MPI_COMM_WORLD, MPI_ERRORS_RETURN);
+
+ // on root, initialize sendbuf
+ if (root == rank) {
+ sndbuf = malloc(size * sizeof(double));
+ for (int i = 0; i < size; i++) {
+ sndbuf[i] = (double) i;
+ }
+ }
+
+ retval = MPI_Scatter(sndbuf, sendcount, MPI_DOUBLE, NULL, recvcount, MPI_DOUBLE, root, MPI_COMM_WORLD);
+ if(retval!=MPI_ERR_BUFFER)
+ printf("MPI_Scatter did not return MPI_ERR_BUFFER for empty recvbuf\n");
+ retval = MPI_Scatter(sndbuf, sendcount, MPI_DOUBLE, &rcvd, -1, MPI_DOUBLE, root, MPI_COMM_WORLD);
+ if(retval!=MPI_ERR_COUNT)
+ printf("MPI_Scatter did not return MPI_ERR_COUNT for -1 recvcount\n");
+ retval = MPI_Scatter(sndbuf, sendcount, MPI_DOUBLE, &rcvd, recvcount, MPI_DATATYPE_NULL, root, MPI_COMM_WORLD);
+ if(retval!=MPI_ERR_TYPE)
+ printf("MPI_Scatter did not return MPI_ERR_TYPE for MPI_DATATYPE_NULL sendtype\n");
+ retval = MPI_Scatter(sndbuf, sendcount, MPI_DOUBLE, &rcvd, recvcount, MPI_DOUBLE, -1, MPI_COMM_WORLD);
+ if(retval!=MPI_ERR_ROOT)
+ printf("MPI_Scatter did not return MPI_ERR_ROOT for root -1\n");
+ retval = MPI_Scatter(sndbuf, sendcount, MPI_DOUBLE, &rcvd, recvcount, MPI_DOUBLE, size+1, MPI_COMM_WORLD);
+ if(retval!=MPI_ERR_ROOT)
+ printf("MPI_Scatter did not return MPI_ERR_ROOT for root > size\n");
+ retval = MPI_Scatter(sndbuf, sendcount, MPI_DOUBLE, &rcvd, recvcount, MPI_DOUBLE, root, MPI_COMM_NULL);
+ if(retval!=MPI_ERR_COMM)
+ printf("MPI_Scatter did not return MPI_ERR_COMM for MPI_COMM_NULL comm\n");
+
+ retval = MPI_Scatter(sndbuf, sendcount, MPI_DOUBLE, &rcvd, recvcount, MPI_DOUBLE, root, MPI_COMM_WORLD);
+ if (root == rank) {
+ free(sndbuf);
+ }
+ if (retval != MPI_SUCCESS) {
+ fprintf(stderr, "(%s:%d) MPI_Scatter() returned retval=%d\n", __FILE__, __LINE__, retval);
+ return 0;
+ }
+ // verification
+ if ((double) rank != rcvd) {
+ fprintf(stderr, "[%d] has %f instead of %d\n", rank, rcvd, rank);
+ success = 0;
+ }