--- /dev/null
+/* -*- Mode: C; c-basic-offset:4 ; -*- */
+/*
+ * (C) 2016 by Argonne National Laboratory.
+ * See COPYRIGHT in top-level directory.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <mpi.h>
+
+#define BUFSIZE 4
+
+/* This program tests nested lock. Process 0 locks the other processes
+ * one by one, then unlock each of them.*/
+
+int main(int argc, char *argv[])
+{
+ int rank = 0, nprocs = 0, dst = 0;
+ int winbuf[BUFSIZE];
+ MPI_Win win = MPI_WIN_NULL;
+
+ MPI_Init(&argc, &argv);
+ MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+ MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
+
+ memset(winbuf, 0, sizeof(int) * BUFSIZE);
+ MPI_Win_create(winbuf, sizeof(int) * BUFSIZE, sizeof(int), MPI_INFO_NULL, MPI_COMM_WORLD, &win);
+
+ if (rank == 0) {
+ /* lock each process */
+ for (dst = 0; dst < nprocs; dst++) {
+ MPI_Win_lock(MPI_LOCK_SHARED, dst, 0, win);
+ }
+
+ /* unlock each process */
+ for (dst = nprocs - 1; dst >= 0; dst--) {
+ MPI_Win_unlock(dst, win);
+ }
+ }
+
+ MPI_Barrier(MPI_COMM_WORLD);
+ MPI_Win_free(&win);
+
+ if (rank == 0) {
+ fprintf(stdout, " No Errors\n");
+ fflush(stdout);
+ }
+
+ MPI_Finalize();
+ return 0;
+}