[svn-r23774] The standalone writer & reader tests that check atomic read-write operation on the system.

4 files changed, 616 insertions, 21 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index 397d20f..50060eb 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -51,7 +51,7 @@ TEST_PROG= testhdf5 lheap ohdr stab gheap cache cache_api cache_tagging \
 
 bin_PROGRAMS=swmr_generator swmr_reader swmr_writer swmr_remove_reader \
     swmr_remove_writer swmr_addrem_writer swmr_sparse_reader swmr_sparse_writer \
-    use_append_chunk use_append_mchunks
+    use_append_chunk use_append_mchunks atomic_writer atomic_reader
 
 # List programs to be built when testing here. error_test and err_compat are
 # built at the same time as the other tests, but executed by testerror.sh.
@@ -162,7 +162,7 @@ CHECK_CLEANFILES+=accum.h5 cmpd_dset.h5 compact_dataset.h5 dataset.h5 \
     swmr_data.h5 use_append_chunk.h5 use_append_mchunks.h5           \
     flushrefresh.h5 flushrefresh_VERIFICATION_START                  \
     flushrefresh_VERIFICATION_CHECKPOINT1 flushrefresh_VERIFICATION_CHECKPOINT2 \
-    flushrefresh_VERIFICATION_DONE
+    flushrefresh_VERIFICATION_DONE atomic_data
 
 # Sources for testhdf5 executable
 testhdf5_SOURCES=testhdf5.c tarray.c tattr.c tchecksum.c tconfig.c tfile.c \
diff --git a/test/Makefile.in b/test/Makefile.in
index b45746f..bbe07d5 100644
--- a/test/Makefile.in
+++ b/test/Makefile.in
@@ -83,7 +83,8 @@ bin_PROGRAMS = swmr_generator$(EXEEXT) swmr_reader$(EXEEXT) \
 	swmr_writer$(EXEEXT) swmr_remove_reader$(EXEEXT) \
 	swmr_remove_writer$(EXEEXT) swmr_addrem_writer$(EXEEXT) \
 	swmr_sparse_reader$(EXEEXT) swmr_sparse_writer$(EXEEXT) \
-	use_append_chunk$(EXEEXT) use_append_mchunks$(EXEEXT)
+	use_append_chunk$(EXEEXT) use_append_mchunks$(EXEEXT) \
+	atomic_writer$(EXEEXT) atomic_reader$(EXEEXT)
 check_PROGRAMS = $(am__EXEEXT_1) error_test$(EXEEXT) \
 	err_compat$(EXEEXT) tcheck_version$(EXEEXT) testmeta$(EXEEXT) \
 	links_env$(EXEEXT) flushrefresh$(EXEEXT) $(am__EXEEXT_2)
@@ -194,6 +195,14 @@ app_ref_SOURCES = app_ref.c
 app_ref_OBJECTS = app_ref.$(OBJEXT)
 app_ref_LDADD = $(LDADD)
 app_ref_DEPENDENCIES = libh5test.la $(LIBHDF5)
+atomic_reader_SOURCES = atomic_reader.c
+atomic_reader_OBJECTS = atomic_reader.$(OBJEXT)
+atomic_reader_LDADD = $(LDADD)
+atomic_reader_DEPENDENCIES = libh5test.la $(LIBHDF5)
+atomic_writer_SOURCES = atomic_writer.c
+atomic_writer_OBJECTS = atomic_writer.$(OBJEXT)
+atomic_writer_LDADD = $(LDADD)
+atomic_writer_DEPENDENCIES = libh5test.la $(LIBHDF5)
 big_SOURCES = big.c
 big_OBJECTS = big.$(OBJEXT)
 big_LDADD = $(LDADD)
@@ -583,12 +592,12 @@ am__v_CCLD_0 = @echo "  CCLD    " $@;
 am__v_CCLD_1 = 
 SOURCES = $(libdynlib1_la_SOURCES) $(libdynlib2_la_SOURCES) \
 	$(libdynlib3_la_SOURCES) $(libh5test_la_SOURCES) accum.c \
-	app_ref.c big.c bittests.c btree2.c cache.c cache_api.c \
-	cache_tagging.c cmpd_dset.c cross_read.c dangle.c dsets.c \
-	dt_arith.c dtransform.c dtypes.c earray.c efc.c \
-	enc_dec_plist.c enc_dec_plist_with_endianess.c enum.c \
-	err_compat.c error_test.c extend.c external.c farray.c fheap.c \
-	file_image.c fillval.c filter_fail.c flush1.c flush2.c \
+	app_ref.c atomic_reader.c atomic_writer.c big.c bittests.c \
+	btree2.c cache.c cache_api.c cache_tagging.c cmpd_dset.c \
+	cross_read.c dangle.c dsets.c dt_arith.c dtransform.c dtypes.c \
+	earray.c efc.c enc_dec_plist.c enc_dec_plist_with_endianess.c \
+	enum.c err_compat.c error_test.c extend.c external.c farray.c \
+	fheap.c file_image.c fillval.c filter_fail.c flush1.c flush2.c \
 	flushrefresh.c freespace.c gen_bad_ohdr.c gen_bogus.c \
 	gen_cross.c gen_deflate.c gen_file_image.c gen_filespace.c \
 	gen_filters.c gen_idx.c gen_new_array.c gen_new_fill.c \
@@ -606,17 +615,18 @@ SOURCES = $(libdynlib1_la_SOURCES) $(libdynlib2_la_SOURCES) \
 DIST_SOURCES = $(am__libdynlib1_la_SOURCES_DIST) \
 	$(am__libdynlib2_la_SOURCES_DIST) \
 	$(am__libdynlib3_la_SOURCES_DIST) $(libh5test_la_SOURCES) \
-	accum.c app_ref.c big.c bittests.c btree2.c cache.c \
-	cache_api.c cache_tagging.c cmpd_dset.c cross_read.c dangle.c \
-	dsets.c dt_arith.c dtransform.c dtypes.c earray.c efc.c \
-	enc_dec_plist.c enc_dec_plist_with_endianess.c enum.c \
-	err_compat.c error_test.c extend.c external.c farray.c fheap.c \
-	file_image.c fillval.c filter_fail.c flush1.c flush2.c \
-	flushrefresh.c freespace.c gen_bad_ohdr.c gen_bogus.c \
-	gen_cross.c gen_deflate.c gen_file_image.c gen_filespace.c \
-	gen_filters.c gen_idx.c gen_new_array.c gen_new_fill.c \
-	gen_new_group.c gen_new_mtime.c gen_new_super.c \
-	gen_noencoder.c gen_nullspace.c gen_plist.c gen_sizes_lheap.c \
+	accum.c app_ref.c atomic_reader.c atomic_writer.c big.c \
+	bittests.c btree2.c cache.c cache_api.c cache_tagging.c \
+	cmpd_dset.c cross_read.c dangle.c dsets.c dt_arith.c \
+	dtransform.c dtypes.c earray.c efc.c enc_dec_plist.c \
+	enc_dec_plist_with_endianess.c enum.c err_compat.c \
+	error_test.c extend.c external.c farray.c fheap.c file_image.c \
+	fillval.c filter_fail.c flush1.c flush2.c flushrefresh.c \
+	freespace.c gen_bad_ohdr.c gen_bogus.c gen_cross.c \
+	gen_deflate.c gen_file_image.c gen_filespace.c gen_filters.c \
+	gen_idx.c gen_new_array.c gen_new_fill.c gen_new_group.c \
+	gen_new_mtime.c gen_new_super.c gen_noencoder.c \
+	gen_nullspace.c gen_plist.c gen_sizes_lheap.c \
 	gen_specmetaread.c gen_udlinks.c getname.c gheap.c hyperslab.c \
 	istore.c lheap.c links.c links_env.c mf.c mount.c mtime.c \
 	ntypes.c objcopy.c ohdr.c plugin.c pool.c reserved.c \
@@ -951,7 +961,7 @@ CHECK_CLEANFILES = *.chkexe *.chklog *.clog accum.h5 cmpd_dset.h5 \
 	flushrefresh.h5 flushrefresh_VERIFICATION_START \
 	flushrefresh_VERIFICATION_CHECKPOINT1 \
 	flushrefresh_VERIFICATION_CHECKPOINT2 \
-	flushrefresh_VERIFICATION_DONE
+	flushrefresh_VERIFICATION_DONE atomic_data
 INCLUDES = -I$(top_srcdir)/src -I$(top_builddir)/src
 
 # Test script for error_test and err_compat
@@ -1216,6 +1226,12 @@ accum$(EXEEXT): $(accum_OBJECTS) $(accum_DEPENDENCIES) $(EXTRA_accum_DEPENDENCIE
 app_ref$(EXEEXT): $(app_ref_OBJECTS) $(app_ref_DEPENDENCIES) $(EXTRA_app_ref_DEPENDENCIES) 
 	@rm -f app_ref$(EXEEXT)
 	$(AM_V_CCLD)$(LINK) $(app_ref_OBJECTS) $(app_ref_LDADD) $(LIBS)
+atomic_reader$(EXEEXT): $(atomic_reader_OBJECTS) $(atomic_reader_DEPENDENCIES) $(EXTRA_atomic_reader_DEPENDENCIES) 
+	@rm -f atomic_reader$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(atomic_reader_OBJECTS) $(atomic_reader_LDADD) $(LIBS)
+atomic_writer$(EXEEXT): $(atomic_writer_OBJECTS) $(atomic_writer_DEPENDENCIES) $(EXTRA_atomic_writer_DEPENDENCIES) 
+	@rm -f atomic_writer$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(atomic_writer_OBJECTS) $(atomic_writer_LDADD) $(LIBS)
 big$(EXEEXT): $(big_OBJECTS) $(big_DEPENDENCIES) $(EXTRA_big_DEPENDENCIES) 
 	@rm -f big$(EXEEXT)
 	$(AM_V_CCLD)$(LINK) $(big_OBJECTS) $(big_LDADD) $(LIBS)
@@ -1480,6 +1496,8 @@ distclean-compile:
 
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/accum.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/app_ref.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/atomic_reader.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/atomic_writer.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/big.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/bittests.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/btree2.Po@am__quote@
diff --git a/test/atomic_reader.c b/test/atomic_reader.c
new file mode 100644
index 0000000..5d9ea68
--- /dev/null
+++ b/test/atomic_reader.c
@@ -0,0 +1,347 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/*-------------------------------------------------------------------------
+ *
+ * Created:    	atomic_reader.c
+ *
+ * Purpose:     This is the "reader" part of the standalone test to check
+ *              atomic read-write operation on a system.
+ *              a) atomic_reader.c--the reader (this file)
+ *              a) atomic_writer.c--the writer
+ *              c) atomic_data--the name of the data file used by writer and reader
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/***********/
+/* Headers */
+/***********/
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+/****************/
+/* Local Macros */
+/****************/
+
+#define FILENAME "atomic_data"
+#define READ_TRIES 20
+#define OPEN_TRIES 50
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+static void usage(void);
+int verify(int fd, unsigned int k);
+void print_info(int *info, unsigned int lastr, unsigned iteration);
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    usage
+ *
+ * Purpose:     To print the command line options
+ *
+ * Parameters:  None
+ *
+ * Return: 	void
+ *
+ *-------------------------------------------------------------------------
+ */
+static void
+usage(void)
+{
+    printf("\n");
+    printf("Usage error!\n");
+    printf("Usage: atomic_reader -n <number of integers to read> -i <number of iterations for reader>\n");
+    printf("       Note**The number of integers for option n has to be positive\n");
+    printf("       Note**The number of integers for option i has to be positive\n");
+    printf("\n");
+} /* usage() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    verify
+ *
+ * Purpose:     To verify that the data read is the pattern expected.
+ *		Each integer read should be the same as the index.
+ *		When a difference is encountered, the remaining integers 
+ *		read should be the same as the previous index.
+ *		For example, the pattern expected should be either:
+ *		a) 01234567....n-1	
+ *		or
+ *		b) if at index 4, a difference is encountered,
+ *		   the remaining integers should be all "3"s as:
+ *			012333333333333
+ *
+ * Parameters:  
+ *	fd--the file descriptor
+ *	k--the number of integers to read
+ *
+ * Return:      
+ *	positive on success
+ *	negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+verify(int fd, unsigned int k)
+{
+    unsigned int i;		/* local index variable */
+    ssize_t bytes_read;		/* the number of bytes read */
+    unsigned int *buf = NULL;	/* buffer to hold data read */
+
+    /* Allocate buffer for data read */
+    if((buf = (unsigned int *)malloc(k * sizeof(unsigned int))) == NULL) {
+	printf("READER: error from malloc\n");
+	goto error;
+    }
+
+    /* Position the file at the beginning */
+    if(lseek(fd, (off_t)0, SEEK_SET) < 0) {
+	printf("READER: error from lseek\n");
+	goto error;
+    }
+
+    /* Read the whole file */
+    if((bytes_read = read(fd, buf, (k * sizeof(unsigned int)))) < 0) {
+	printf("READER: error from read\n");
+	goto error;
+    }
+
+    /* Verify the bytes read are correct */
+    if(bytes_read != (ssize_t)(k*sizeof(unsigned int))) {
+	printf("READER: error from bytes read=%lu\n", (unsigned long)bytes_read);
+	goto error;
+    }
+
+    /* Verify data read */
+    for(i=0; i < k; i++)  {
+	if(buf[i] != i)
+	    break;
+    }
+
+    if(i < k) {
+	/* Compare the beginning and ending sentinel values */
+	if(buf[k-1] != (i-1)) {
+	    printf("FAIL IN READER: ...beginning sentinel value=%u, i=%u\n", (i-1), i);
+	    printf("FAIL IN READER: buf[%u]=%u\n", i-1, buf[i-1]);
+	    printf("FAIL IN READER: buf[%u]=%u\n", i, buf[i]);
+	    printf("FAIL IN READER: buf[%u]=%u\n", i+1, buf[i+1]);
+	    printf("FAIL IN READER: ...ending sentinel value=%u\n", buf[k-1]);
+	    goto error;
+	}
+    }
+
+    /* Free the buffer */
+    if(buf) free(buf);
+    return(0);
+
+error:
+    /* Free the buffer */
+    if(buf) free(buf);
+    return(-1);
+} /* verify() */
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    print_info
+ *
+ * Purpose:     To print the statistics gathered for re-reads
+ *
+ * Parameters: 
+ *	info--the array storing the statistics for re-reads
+ *	lastr--the last read completed
+ *	iteration--the current iteration
+ *
+ * Return:     	void
+ *
+ *-------------------------------------------------------------------------
+ */
+void
+print_info(int *info, unsigned int lastr, unsigned iteration)
+{
+    unsigned j;	/* local index variable */
+
+    printf("--------statistics for %u reads (iteration %u)--------\n", lastr, iteration);
+
+    for(j = 0; j <= READ_TRIES; j++)
+	printf("# of %u re-tries = %u\n", j, info[j]);
+
+    printf("--------end statistics for %u reads (iteration %u)--------\n", lastr, iteration);
+} /* print_info() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    main
+ *
+ * Purpose:     To verify that the data read is the pattern expected.
+ *		(1) Make sure the file opens successfully and the # of bytes read is as expected	
+ *		(2) Iterate the reader with i iterations 
+ *		(3) Read and verify n integers for each iteration
+ *		(4) On verification error, re-read the data at most READ_TRIES
+ *	  	    times to see if correct data can be obtained
+ *		(5) Print out statistics for the number of re-retries for each iteration
+ *
+ * Note:
+ *      (a) The # of integers (via -n option) used by the writer and reader should be the same.
+ *      (b) The data file used by the writer and reader should be the same.
+ *
+ * Future enhancement:
+ *      1) Provide default values for n and i and allow user to run with either 0 or 1 option
+ *      2) Use HDF library HD<system calls> instead of the system calls
+ *      3) Handle large sized buffer (gigabytes) if needed
+ *
+ * Return:      Success:       0
+ *              Failure:       -1
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+main(int argc, char *argv[])
+{
+    int fd = -1;			/* file descriptor */
+    unsigned int j=0, i=0, m=0;		/* local index variables */
+    int temp;				/* temporary variable */
+    unsigned int iterations = 0;	/* the input for "-i" */
+    unsigned num = 0;			/* the input for "-n" */
+    int opt = 0;			/* option char */
+    int info[READ_TRIES+1];		/* re-tries statistics */
+
+    /* Ensure the expected # of arguments */
+    if(argc != 5) {
+        usage();
+	exit(-1);
+    }
+
+    /* Parse command line options */
+    while((opt = getopt(argc, argv, "n:i:")) != -1) {
+        switch(opt) {
+            case 'n':
+                if((temp = atoi(optarg)) < 0) {
+                    usage();
+		    exit(-1);
+		}
+                num = (unsigned int)temp;
+                break;
+            case 'i':
+                if((temp = atoi(optarg)) < 0) {
+                    usage();
+		    exit(-1);
+		}
+                iterations = (unsigned int)temp;
+                break;
+            default:
+                printf("Invalid option encountered\n");
+                break;
+        }
+    }
+
+    printf("READER: number of integers to read = %u; # of iterations = %d\n", num, iterations);
+
+    printf("\n");
+    for(i = 1; i <= iterations; i++) { /* iteration loop */
+	unsigned opens = OPEN_TRIES;
+
+	printf("READER: *****start iteration %u*****\n", i);
+
+	/* Ensure open and file size are done properly */
+	while(opens--) { /* open loop */
+	    struct stat sinfo;
+
+	    memset(&sinfo, 0, sizeof(sinfo));
+
+	    if((fd = open(FILENAME, O_RDONLY, 0644)) < 0) {
+		printf("READER: error from open--retry open again\n");
+	    } else {
+		printf("READER: open succeed\n");
+
+		if((fstat(fd, &sinfo) == 0) &&
+		   (sinfo.st_size == (off_t)(num * sizeof(unsigned int)))) {
+		    printf("READER: file size is correct--%u\n", (unsigned int)sinfo.st_size);
+		    break;
+		}
+
+		printf("READER: error from fstat or file size of %u is incorrect--retry open again\n", (unsigned int)sinfo.st_size);
+		if(close(fd) < 0) {
+		    printf("READER: error from close\n");
+		    return(-1);
+		}
+		fd = -1;
+	    }
+
+	} /* end while */
+
+	if(fd < 0) {
+	    printf("READER: *****open failure/incorrect file size for all %u tries, continue next iteration*****\n\n", OPEN_TRIES);
+	    continue;
+	}
+
+	memset(info, 0, sizeof(info));
+
+	/* Read and verify data */
+	for(j = 1; j <= num; j++) { /* read loop */
+
+	    printf("READER: doing read %u\n", j);
+	    if(verify(fd, num) < 0) {
+		printf("READER: error from read %u\n", j);
+
+		/* Perform re-read to see if correct data is obtained */
+		for(m = 1; m <= READ_TRIES; m++) { /* re-read loop */
+		    printf("READER: ===============going to do re-read try %u\n", m);
+		    if(verify(fd, num) < 0)
+			printf("READER: ===============error from re-read try %u\n", m);
+		    else {
+			++info[m];
+			printf("READER: ===============SUCCESS from re-read try %u\n", m);
+			break;
+		    }
+		} /* end for */
+
+		if(m > READ_TRIES) {
+		    printf("READER: ===============error from all re-read tries: %u\n", READ_TRIES);
+		    printf("READER:*****ERROR--stop on read %u\n", j);
+		    break;
+		}
+	    } else {
+		++info[0];
+		printf("READER: success from read %u\n", j);
+	    }
+
+	} /* end for */
+
+	/* Print the statistics for re-reads */
+	print_info(info, j-1, i);
+
+	/* Close the file */
+	if(close(fd) < 0) {
+	    printf("READER: error from close\n");
+	    return(-1);
+	}
+
+	printf("READER: *****end iteration %u*****\n\n", i);
+
+    } /* end for */
+
+    return(0);
+}
diff --git a/test/atomic_writer.c b/test/atomic_writer.c
new file mode 100644
index 0000000..9f37ecc
--- /dev/null
+++ b/test/atomic_writer.c
@@ -0,0 +1,230 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:    	atomic_writer.c
+ *
+ * Purpose:   	This is the "writer" part of the standalone test to check 
+ *		atomic read-write operation on a system.
+ *		a) atomic_writer.c--the writer (this file)
+ *		b) atomic_reader.c--the reader
+ *		c) atomic_data--the name of the data file used by writer and reader
+ *		
+ *-------------------------------------------------------------------------
+ */
+
+/***********/
+/* Headers */
+/***********/
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+
+/****************/
+/* Local Macros */
+/****************/
+
+#define FILENAME "atomic_data"
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+static void usage(void);
+
+
+/*-------------------------------------------------------------------------
+ * Function:    usage
+ *
+ * Purpose:     To print information about the command line options
+ *
+ * Parameters: 	None
+ *
+ * Return:   	void
+ *
+ *-------------------------------------------------------------------------
+ */
+static void
+usage(void)
+{
+    printf("\n");
+    printf("Usage error!\n");
+    printf("Usage: atomic_writer -n <number of integers to write> -i <number of iterations for writer>\n");
+    printf("       Note**The number of integers for option n has to be positive\n");
+    printf("       Note**The number of integers for option i has to be positive\n");
+    printf("\n");
+} /* usage() */
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    main
+ *
+ * Purpose: 	To write a series of integers to a file for the reader to verify the data.
+ *		A write is atomic if the whole amount written in one operation is not interleaved 
+ *		with data from any other process.
+ *		(1) Iterate with i iterations
+ *		(2) Write a series of integers (0 to n-1) to the file with this pattern:
+ *		offset 0: 	0000000000000000000000000000000
+ *		offset 1:  	 111111111111111111111111111111
+ *		offset 2:   	  22222222222222222222222222222
+ *		offset 3:    	   3333333333333333333333333333
+ *		...
+ *		...
+ *		offset n-1: 		 		  (n-1)
+ *
+ *		At the end of the writes, the data in the file will be:
+ *		01234567........(n-1)
+ *
+ * Note:
+ *      (a) The # of integers (via -n option) used by the writer and reader should be the same.
+ *      (b) The data file used by the writer and reader should be the same.
+ *
+ * Future enhancement:
+ *      1) Provide default values for n and i and allow user to run with either 0 or 1 option
+ *      2) Use HDF library HD<system calls> instead of the system calls
+ *      3) Handle large sized buffer (gigabytes) if needed
+ *	
+ * Return:      Success:      0
+ *              Failure:      -1
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+main(int argc, char *argv[])
+{
+    int fd = -1;			/* file descriptor */
+    ssize_t bytes_wrote;		/* the nubmer of bytes written */
+    unsigned int *buf = NULL;		/* buffer to hold written data */
+    unsigned int n, u, i;		/* local index variable */
+    int temp;				/* temporary variable */
+    unsigned int iterations = 0;	/* the input for "-i" */
+    unsigned int num = 0;		/* the input for "-n" */
+    int opt = 0;			/* option char */
+
+    /* Ensure the # of arguments is as expected */
+    if(argc != 5) {
+        usage();
+	exit(-1);
+    }
+
+    /* Parse command line options */
+    while((opt = getopt(argc, argv, "n:i:")) != -1) {
+	switch(opt) {
+	    case 'n':
+		if((temp = atoi(optarg)) < 0) {
+		    usage();
+		    exit(-1);
+		}
+		num = (unsigned int)temp;
+		break;
+	    case 'i':
+		if((temp = atoi(optarg)) < 0) {
+		    usage();
+		    exit(-1);
+		}
+		iterations = (unsigned int)temp;
+		break;
+	    default:
+		printf("Invalid option encountered\n");
+		break;
+	}
+    }
+
+    printf("WRITER: # of integers to write = %u; # of iterations = %d\n", num, iterations);
+
+    /* Remove existing data file if needed */
+    if(remove(FILENAME) < 0) {
+	if(errno == ENOENT)
+	    printf("WRITER: remove %s--%s\n", FILENAME, strerror(errno));
+	else {
+	    printf("WRITER: error from remove: %d--%s\n", errno, strerror(errno));
+	    goto error;
+	}
+    } else
+	printf("WRITER: %s is removed\n", FILENAME);
+
+    /* Create the data file */
+    if((fd = open(FILENAME, O_RDWR|O_TRUNC|O_CREAT, 0664)) < 0) {
+	printf("WRITER: error from open\n");
+	goto error;
+    }
+
+    /* Allocate buffer for holding data to be written */
+    if((buf = (unsigned int *)malloc(num * sizeof(unsigned int))) == NULL) {
+	printf("WRITER: error from malloc\n");
+	if(fd >= 0 && close(fd) < 0)
+	    printf("WRITER: error from close\n");
+	goto error;
+    }
+
+    printf("\n");
+
+    for(i = 1; i <= iterations; i++) { /* iteration loop */
+	printf("WRITER: *****start iteration %u*****\n", i);
+
+	/* Write the series of integers to the file */
+	for(n = 0; n < num; n++)  { /* write loop */
+
+	    /* Set up data to be written */
+	    for(u=0; u < num; u++)
+		buf[u] = n;
+
+	    /* Position the file to the proper location */
+	    if(lseek(fd, (off_t)(n*sizeof(unsigned int)), SEEK_SET) < 0) {
+		printf("WRITER: error from lseek\n");
+		goto error;
+	    }
+    
+	    /* Write the data */
+	    if((bytes_wrote = write(fd, buf, ((num-n) * sizeof(unsigned int)))) < 0) {
+		printf("WRITER: error from write\n");
+		goto error;
+	    }
+
+	    /* Verify the bytes written is correct */
+	    if(bytes_wrote != (ssize_t)((num-n) * sizeof(unsigned int))) {
+		printf("WRITER: error from bytes written\n");
+		goto error;
+	    }
+	} /* end for */
+
+	printf("WRITER: *****end iteration %u*****\n\n", i);
+
+    } /* end for */
+
+    /* Close the file */
+    if(close(fd) < 0) {
+	printf("WRITER: error from close\n");
+	goto error;
+    }
+
+    /* Free the buffer */
+    if(buf) free(buf);
+
+    return(0);
+
+error:
+    return(-1);
+} /* main() */