summaryrefslogtreecommitdiffstats
path: root/tests/main.test
blob: 0f256370e3bee6d6af1694259f7ed04930e51f14 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
# This file contains tests for the tkMain.c file.
#
# This file contains a collection of tests for one or more of the Tcl
# built-in commands.  Sourcing this file into Tcl runs the tests and
# generates output for errors.  No output means no errors were found.
#
# Copyright (c) 1997 by Sun Microsystems, Inc.
# Copyright (c) 1998-1999 by Scriptics Corporation.
# All rights reserved.
#
# RCS: @(#) $Id: main.test,v 1.6 2002/07/13 20:28:35 dgp Exp $

package require tcltest 2.1
namespace import -force tcltest::configure
namespace import -force tcltest::testsDirectory
configure -testdir [file join [pwd] [file dirname [info script]]]
configure -loadfile [file join [testsDirectory] constraints.tcl]
tcltest::loadTestedCommands

namespace import -force tcltest::interpreter
namespace import -force tcltest::makeFile
namespace import -force tcltest::removeFile

test main-1.1 {StdinProc} {unix} {
    set script [makeFile {
	close stdin; exit
    } script]
    if {[catch {exec [interpreter] <$script} msg]} {
	set error 1
    } else {
	set error 0
    }
    removeFile script
    list $error $msg
} {0 {}}

# cleanup
::tcltest::cleanupTests
return













'>486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * 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.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * MPIO independent overlapping writes.
 *
 * First n-1 processes open 1 file.
 * Each of the n-1 process writes chunks of data to the file in round-robin
 * fashion, in a interleaved but not overlapped fashion.  Using increasing
 * chunk sizes for the benefits of testing different write sizes and also
 * reducing the numbers of writes.
 *
 * Last process (n-1) just waits.
 * First n-1 processes finish writing and cloose the file.
 * Last process opens the same file and verifies the data.
 */

#include "testpar.h"

/* FILENAME and filenames must have the same number of names */
const char *FILENAME[2]={
	    "MPItest",
	    NULL};
char	filenames[2][200];
int	nerrors = 0;
hid_t	fapl;				/* file access property list */

/* protocols */
static int errors_sum(int nerrs);

#define MPIO_TEST_WRITE_SIZE 1024*1024     /* 1 MB */

static int
test_mpio_overlap_writes(char *filename)
{
    int mpi_size, mpi_rank;
    MPI_Comm comm;
    MPI_Info info = MPI_INFO_NULL;
    int color, mrc;
    MPI_File	fh;
    int i;
    int vrfyerrs, nerrs;
    unsigned char  buf[4093];		/* use some prime number for size */
    int bufsize = sizeof(buf);
    MPI_Offset  stride;
    MPI_Offset  mpi_off;
    MPI_Status  mpi_stat;


    if (VERBOSE_MED)
	printf("MPIO independent overlapping writes test on file %s\n",
	    filename);

    nerrs = 0;
    /* set up MPI parameters */
    MPI_Comm_size(MPI_COMM_WORLD,&mpi_size);
    MPI_Comm_rank(MPI_COMM_WORLD,&mpi_rank);

    /* Need at least 2 processes */
    if (mpi_size < 2) {
	if (MAINPROCESS)
	    printf("Need at least 2 processes to run MPIO test.\n");
	    printf(" -SKIP- \n");
	return 0;
    }

    /* splits processes 0 to n-2 into one comm. and the last one into another */
    color = ((mpi_rank < (mpi_size - 1)) ? 0 : 1);
    mrc = MPI_Comm_split (MPI_COMM_WORLD, color, mpi_rank, &comm);
    VRFY((mrc==MPI_SUCCESS), "Comm_split succeeded");

    if (color==0){
	/* First n-1 processes (color==0) open a file and write it */
	mrc = MPI_File_open(comm, filename, MPI_MODE_CREATE|MPI_MODE_RDWR,
		info, &fh);
	VRFY((mrc==MPI_SUCCESS), "");

	stride = 1;
	mpi_off = mpi_rank*stride;
	while (mpi_off < MPIO_TEST_WRITE_SIZE){
	    /* make sure the write does not exceed the TEST_WRITE_SIZE */
	    if (mpi_off+stride > MPIO_TEST_WRITE_SIZE)
		stride = MPIO_TEST_WRITE_SIZE - mpi_off;

	    /* set data to some trivial pattern for easy verification */
	    for (i=0; i<stride; i++)
		buf[i] = (unsigned char)(mpi_off+i);
	    mrc = MPI_File_write_at(fh, mpi_off, buf, (int)stride, MPI_BYTE,
		    &mpi_stat);
	    VRFY((mrc==MPI_SUCCESS), "");

	    /* move the offset pointer to last byte written by all processes */
	    mpi_off += (mpi_size - 1 - mpi_rank) * stride;

	    /* Increase chunk size without exceeding buffer size. */
	    /* Then move the starting offset for next write. */
	    stride *= 2;
	    if (stride > bufsize)
		stride = bufsize;
	    mpi_off += mpi_rank*stride;
	}

	/* close file and free the communicator */
	mrc = MPI_File_close(&fh);
	VRFY((mrc==MPI_SUCCESS), "MPI_FILE_CLOSE");
	mrc = MPI_Comm_free(&comm);
	VRFY((mrc==MPI_SUCCESS), "MPI_Comm_free");

	/* sync with the other waiting processes */
	mrc = MPI_Barrier(MPI_COMM_WORLD);
	VRFY((mrc==MPI_SUCCESS), "Sync after writes");
    }else{
	/* last process waits till writes are done,
	 * then opens file to verify data.
	 */
	mrc = MPI_Barrier(MPI_COMM_WORLD);
	VRFY((mrc==MPI_SUCCESS), "Sync after writes");

	mrc = MPI_File_open(comm, filename, MPI_MODE_RDONLY,
		info, &fh);
	VRFY((mrc==MPI_SUCCESS), "");

	stride = bufsize;
	for (mpi_off=0; mpi_off < MPIO_TEST_WRITE_SIZE; mpi_off += bufsize){
	    /* make sure it does not read beyond end of data */
	    if (mpi_off+stride > MPIO_TEST_WRITE_SIZE)
		stride = MPIO_TEST_WRITE_SIZE - mpi_off;
	    mrc = MPI_File_read_at(fh, mpi_off, buf, (int)stride, MPI_BYTE,
		    &mpi_stat);
	    VRFY((mrc==MPI_SUCCESS), "");
	    vrfyerrs=0;
	    for (i=0; i<stride; i++){
		unsigned char expected;
		expected = (unsigned char)(mpi_off+i);
		if ((expected != buf[i]) &&
		    (vrfyerrs++ < MAX_ERR_REPORT || VERBOSE_MED)) {
			printf("proc %d: found data error at [%ld], expect %u, got %u\n",
			    mpi_rank, (long)(mpi_off+i), expected, buf[i]);
		}
	    }
	    if (vrfyerrs > MAX_ERR_REPORT && !VERBOSE_MED)
		printf("proc %d: [more errors ...]\n", mpi_rank);

	    nerrs += vrfyerrs;
	}

	/* close file and free the communicator */
	mrc = MPI_File_close(&fh);
	VRFY((mrc==MPI_SUCCESS), "MPI_FILE_CLOSE");
	mrc = MPI_Comm_free(&comm);
	VRFY((mrc==MPI_SUCCESS), "MPI_Comm_free");
    }

    /*
     * one more sync to ensure all processes have done reading
     * before ending this test.
     */
    mrc = MPI_Barrier(MPI_COMM_WORLD);
    VRFY((mrc==MPI_SUCCESS), "Sync before leaving test");
    return (nerrs);
}


#define MB      1048576        /* 1024*1024 == 2**20 */
#define GB      1073741824     /* 1024**3 == 2**30 */
#define TWO_GB_LESS1    2147483647     /* 2**31 - 1 */
#define FOUR_GB_LESS1   4294967295L     /* 2**32 - 1 */
/*
 * Verify that MPI_Offset exceeding 2**31 can be computed correctly.
 * Print any failure as information only, not as an error so that this
 * won't abort the remaining test or other separated tests.
 *
 * Test if MPIO can write file from under 2GB to over 2GB and then
 * from under 4GB to over 4GB.
 * Each process writes 1MB in round robin fashion.
 * Then reads the file back in by reverse order, that is process 0
 * reads the data of process n-1 and vice versa.
 */
static int
test_mpio_gb_file(char *filename)
{
    int mpi_size, mpi_rank;
    MPI_Info info = MPI_INFO_NULL;
    int mrc;
    MPI_File	fh;
    int i, j, n;
    int vrfyerrs;
    int writerrs;		/* write errors */
    int nerrs;
    int ntimes;			/* how many times */
    char  *buf = NULL;
    char  expected;
    MPI_Offset  size;
    MPI_Offset  mpi_off;
    MPI_Offset  mpi_off_old;
    MPI_Status  mpi_stat;
    struct stat stat_buf;
    int is_signed, sizeof_mpi_offset;

    nerrs = 0;
    /* set up MPI parameters */
    MPI_Comm_size(MPI_COMM_WORLD,&mpi_size);
    MPI_Comm_rank(MPI_COMM_WORLD,&mpi_rank);

    if (VERBOSE_MED)
        printf("MPI_Offset range test\n");

    /* figure out the signness and sizeof MPI_Offset */
    mpi_off = 0;
    is_signed = ((MPI_Offset)(mpi_off - 1)) < 0;
    sizeof_mpi_offset = (int)(sizeof(MPI_Offset));

    /*
     * Verify the sizeof MPI_Offset and correctness of handling multiple GB
     * sizes.
     */
    if (MAINPROCESS){			/* only process 0 needs to check it*/
	printf("MPI_Offset is %s %d bytes integeral type\n",
	    is_signed ? "signed" : "unsigned", (int)sizeof(MPI_Offset));
	if (sizeof_mpi_offset <= 4 && is_signed){
	    printf("Skipped 2GB range test "
		    "because MPI_Offset cannot support it\n");
	}else {
	    /* verify correctness of assigning 2GB sizes */
	    mpi_off = 2 * 1024 * (MPI_Offset)MB;
	    INFO((mpi_off>0), "2GB OFFSET assignment no overflow");
	    INFO((mpi_off-1)==TWO_GB_LESS1, "2GB OFFSET assignment succeed");

	    /* verify correctness of increasing from below 2 GB to above 2GB */
	    mpi_off = TWO_GB_LESS1;
	    for (i=0; i < 3; i++){
		mpi_off_old = mpi_off;
		mpi_off = mpi_off + 1;
		/* no overflow */
		INFO((mpi_off>0), "2GB OFFSET increment no overflow");
		/* correct inc. */
		INFO((mpi_off-1)==mpi_off_old, "2GB OFFSET increment succeed");
	    }
	}

	if (sizeof_mpi_offset <= 4){
	    printf("Skipped 4GB range test "
		    "because MPI_Offset cannot support it\n");
	}else {
	    /* verify correctness of assigning 4GB sizes */
	    mpi_off = 4 * 1024 * (MPI_Offset)MB;
	    INFO((mpi_off>0), "4GB OFFSET assignment no overflow");
	    INFO((mpi_off-1)==FOUR_GB_LESS1, "4GB OFFSET assignment succeed");

	    /* verify correctness of increasing from below 4 GB to above 4 GB */
	    mpi_off = FOUR_GB_LESS1;
	    for (i=0; i < 3; i++){
		mpi_off_old = mpi_off;
		mpi_off = mpi_off + 1;
		/* no overflow */
		INFO((mpi_off>0), "4GB OFFSET increment no overflow");
		/* correct inc. */
		INFO((mpi_off-1)==mpi_off_old, "4GB OFFSET increment succeed");
	    }
	}
    }

    /*
     * Verify if we can write to a file of multiple GB sizes.
     */
    if (VERBOSE_MED)
	printf("MPIO GB file test %s\n", filename);

    if (sizeof_mpi_offset <= 4){
	printf("Skipped GB file range test "
		"because MPI_Offset cannot support it\n");
    }else{
	buf = malloc(MB);
	VRFY((buf!=NULL), "malloc succeed");

	/* open a new file. Remove it first in case it exists. */
	/* Must delete because MPI_File_open does not have a Truncate mode. */
	/* Don't care if it has error. */
	MPI_File_delete(filename, MPI_INFO_NULL);
	MPI_Barrier(MPI_COMM_WORLD);	/* prevent racing condition */

	mrc = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE|MPI_MODE_RDWR,
		    info, &fh);
	VRFY((mrc==MPI_SUCCESS), "MPI_FILE_OPEN");

	printf("MPIO GB file write test %s\n", filename);

	/* instead of writing every bytes of the file, we will just write
	 * some data around the 2 and 4 GB boundaries.  That should cover
	 * potential integer overflow and filesystem size limits.
	 */
	writerrs = 0;
	for (n=2; n <= 4; n+=2){
	    ntimes = GB/MB*n/mpi_size + 1;
	    for (i=ntimes-2; i <= ntimes; i++){
		mpi_off = (i*mpi_size + mpi_rank)*(MPI_Offset)MB;
		if (VERBOSE_MED)
		    HDfprintf(stdout,"proc %d: write to mpi_off=%016llx, %lld\n",
			mpi_rank, mpi_off, mpi_off);
		/* set data to some trivial pattern for easy verification */
		for (j=0; j<MB; j++)
		    *(buf+j) = i*mpi_size + mpi_rank;
		if (VERBOSE_MED)
		    HDfprintf(stdout,"proc %d: writing %d bytes at offset %lld\n",
			mpi_rank, MB, mpi_off);
		mrc = MPI_File_write_at(fh, mpi_off, buf, MB, MPI_BYTE, &mpi_stat);
		INFO((mrc==MPI_SUCCESS), "GB size file write");
		if (mrc!=MPI_SUCCESS)
		    writerrs++;
	    }
	}

	/* close file and free the communicator */
	mrc = MPI_File_close(&fh);
	VRFY((mrc==MPI_SUCCESS), "MPI_FILE_CLOSE");

	mrc = MPI_Barrier(MPI_COMM_WORLD);
	VRFY((mrc==MPI_SUCCESS), "Sync after writes");

	/*
	 * Verify if we can read the multiple GB file just created.
	 */
	/* open it again to verify the data written */
	/* but only if there was no write errors */
	printf("MPIO GB file read test %s\n", filename);
	if (errors_sum(writerrs)>0){
	    printf("proc %d: Skip read test due to previous write errors\n",
		mpi_rank);
	    goto finish;
	}
	mrc = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_RDONLY, info, &fh);
	VRFY((mrc==MPI_SUCCESS), "");

	/* Only read back parts of the file that have been written. */
	for (n=2; n <= 4; n+=2){
	    ntimes = GB/MB*n/mpi_size + 1;
	    for (i=ntimes-2; i <= ntimes; i++){
		mpi_off = (i*mpi_size + (mpi_size - mpi_rank - 1))*(MPI_Offset)MB;
		if (VERBOSE_MED)
		    HDfprintf(stdout,"proc %d: read from mpi_off=%016llx, %lld\n",
			mpi_rank, mpi_off, mpi_off);
		mrc = MPI_File_read_at(fh, mpi_off, buf, MB, MPI_BYTE, &mpi_stat);
		INFO((mrc==MPI_SUCCESS), "GB size file read");
		expected = i*mpi_size + (mpi_size - mpi_rank - 1);
		vrfyerrs=0;
		for (j=0; j<MB; j++){
		    if ((*(buf+j) != expected) &&
			(vrfyerrs++ < MAX_ERR_REPORT || VERBOSE_MED)){
			    printf("proc %d: found data error at [%ld+%d], expect %d, got %d\n",
				mpi_rank, (long)mpi_off, j, expected, *(buf+j));
		    }
		}
		if (vrfyerrs > MAX_ERR_REPORT && !VERBOSE_MED)
		    printf("proc %d: [more errors ...]\n", mpi_rank);

		nerrs += vrfyerrs;
	    }
	}

	/* close file and free the communicator */
	mrc = MPI_File_close(&fh);
	VRFY((mrc==MPI_SUCCESS), "MPI_FILE_CLOSE");

	/*
	 * one more sync to ensure all processes have done reading
	 * before ending this test.
	 */
	mrc = MPI_Barrier(MPI_COMM_WORLD);
	VRFY((mrc==MPI_SUCCESS), "Sync before leaving test");

        /*
         * Check if MPI_File_get_size works correctly.  Some systems (only SGI Altix
         * Propack 4 so far) return wrong file size.  It can be avoided by reconfiguring
         * with "--disable-mpi-size".
         */
#ifdef H5_HAVE_MPI_GET_SIZE
	printf("Test if MPI_File_get_size works correctly with %s\n", filename);

	mrc = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_RDONLY, info, &fh);
        VRFY((mrc==MPI_SUCCESS), "");

        if (MAINPROCESS){			/* only process 0 needs to check it*/
            mrc = MPI_File_get_size(fh, &size);
	    VRFY((mrc==MPI_SUCCESS), "");

            mrc=stat(filename, &stat_buf);
	    VRFY((mrc==0), "");

            /* Hopefully this casting is safe */
            if(size != (MPI_Offset)(stat_buf.st_size)) {
                printf("Warning: MPI_File_get_size doesn't return correct file size.  To avoid using it in the library, reconfigure and rebuild the library with --disable-mpi-size.\n");
            }
        }

	/* close file and free the communicator */
	mrc = MPI_File_close(&fh);
	VRFY((mrc==MPI_SUCCESS), "MPI_FILE_CLOSE");

	/*
	 * one more sync to ensure all processes have done reading
	 * before ending this test.
	 */
	mrc = MPI_Barrier(MPI_COMM_WORLD);
	VRFY((mrc==MPI_SUCCESS), "Sync before leaving test");
#else
        printf("Skipped testing MPI_File_get_size because it's disabled\n");
#endif
    }

finish:
    if (buf)
	HDfree(buf);
    return (nerrs);
}


/*
 * MPI-IO Test: One writes, Many reads.
 * Verify if only one process writes some data and then all other
 * processes can read them back correctly. This tests if the
 * underlaying parallel I/O and file system supports parallel I/O
 * correctly.
 *
 * Algorithm: Only one process (e.g., process 0) writes some data.
 * Then all processes, including the writing process, read the data
 * back and verify them against the original values.
 */

/*
 * Default filename can be specified via first program argument.
 * Each process writes something, then reads all data back.
 */

#define DIMSIZE	32		/* Dimension size. */
#define PRINTID printf("Proc %d: ", mpi_rank)
#define USENONE 0
#define USEATOM 1		/* request atomic I/O */
#define USEFSYNC 2		/* request file_sync */


static int
test_mpio_1wMr(char *filename, int special_request)
{
    char hostname[128];
    int  mpi_size, mpi_rank;
    MPI_File fh;
    char mpi_err_str[MPI_MAX_ERROR_STRING];
    int  mpi_err_strlen;
    int  mpi_err;
    unsigned char writedata[DIMSIZE], readdata[DIMSIZE];
    unsigned char expect_val;
    int  i, irank;
    int  nerrs = 0;		/* number of errors */
    int  atomicity;
    MPI_Offset  mpi_off;
    MPI_Status  mpi_stat;

    MPI_Comm_size(MPI_COMM_WORLD, &mpi_size);
    MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);

    if (MAINPROCESS && VERBOSE_MED){
        printf("Testing one process writes, all processes read.\n");
	printf("Using %d processes accessing file %s\n", mpi_size, filename);
        printf("    (Filename can be specified via program argument)\n");
    }

    /* show the hostname so that we can tell where the processes are running */
    if (VERBOSE_DEF){
	if (gethostname(hostname, 128) < 0){
	    PRINTID;
	    printf("gethostname failed\n");
	    return 1;
	}
	PRINTID;
	printf("hostname=%s\n", hostname);
    }

    /* Delete any old file in order to start anew. */
    /* Must delete because MPI_File_open does not have a Truncate mode. */
    /* Don't care if it has error. */
    MPI_File_delete(filename, MPI_INFO_NULL);
    MPI_Barrier(MPI_COMM_WORLD);	/* prevent racing condition */

    if ((mpi_err = MPI_File_open(MPI_COMM_WORLD, filename,
	    MPI_MODE_RDWR | MPI_MODE_CREATE ,
	    MPI_INFO_NULL, &fh))
	    != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	PRINTID;
	printf("MPI_File_open failed (%s)\n", mpi_err_str);
	return 1;
    }

if (special_request & USEATOM){
    /* ==================================================
     * Set atomcity to true (1).  A POSIX compliant filesystem
     * should not need this.
     * ==================================================*/
    if ((mpi_err = MPI_File_get_atomicity(fh, &atomicity)) != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	PRINTID;
	printf("MPI_File_get_atomicity failed (%s)\n", mpi_err_str);
    }
    if (VERBOSE_HI)
	printf("Initial atomicity = %d\n", atomicity);
    if ((mpi_err = MPI_File_set_atomicity(fh, 1)) != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	PRINTID;
	printf("MPI_File_set_atomicity failed (%s)\n", mpi_err_str);
    }
    if ((mpi_err = MPI_File_get_atomicity(fh, &atomicity)) != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	PRINTID;
	printf("MPI_File_get_atomicity failed (%s)\n", mpi_err_str);
    }
    if (VERBOSE_HI)
	printf("After set_atomicity atomicity = %d\n", atomicity);
}

    /* This barrier is not necessary but do it anyway. */
    MPI_Barrier(MPI_COMM_WORLD);
    if (VERBOSE_HI){
	PRINTID;
	printf("between MPI_Barrier and MPI_File_write_at\n");
    }

    /* ==================================================
     * Each process calculates what to write but
     * only process irank(0) writes.
     * ==================================================*/
    irank=0;
    for (i=0; i < DIMSIZE; i++)
	writedata[i] = irank*DIMSIZE + i;
    mpi_off = irank*DIMSIZE;

    /* Only one process writes */
    if (mpi_rank==irank){
	if (VERBOSE_HI){
	    PRINTID; printf("wrote %d bytes at %ld\n", DIMSIZE, (long)mpi_off);
	}
	if ((mpi_err = MPI_File_write_at(fh, mpi_off, writedata, DIMSIZE,
			MPI_BYTE, &mpi_stat))
		!= MPI_SUCCESS){
	    MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	    PRINTID;
	    printf("MPI_File_write_at offset(%ld), bytes (%d), failed (%s)\n",
		    (long) mpi_off, DIMSIZE, mpi_err_str);
	    return 1;
	};
    };

    /* Bcast the return code and */
    /* make sure all writing are done before reading. */
    MPI_Bcast(&mpi_err, 1, MPI_INT, irank, MPI_COMM_WORLD);
    if (VERBOSE_HI){
	PRINTID;
	printf("MPI_Bcast: mpi_err = %d\n", mpi_err);
    }

if (special_request & USEFSYNC){
    /* ==================================================
     * Do a file sync.  A POSIX compliant filesystem
     * should not need this.
     * ==================================================*/
    if (VERBOSE_HI)
	printf("Apply MPI_File_sync\n");
    /* call file_sync to force the write out */
    if ((mpi_err = MPI_File_sync(fh)) != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	PRINTID;
	printf("MPI_File_sync failed (%s)\n", mpi_err_str);
    }
    MPI_Barrier(MPI_COMM_WORLD);
    /* call file_sync to force the write out */
    if ((mpi_err = MPI_File_sync(fh)) != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	PRINTID;
	printf("MPI_File_sync failed (%s)\n", mpi_err_str);
    }
}

    /* This barrier is not necessary because the Bcase or File_sync above */
    /* should take care of it.  Do it anyway. */
    MPI_Barrier(MPI_COMM_WORLD);
    if (VERBOSE_HI){
	PRINTID;
	printf("after MPI_Barrier\n");
    }

    /* ==================================================
     * Each process reads what process 0 wrote and verify.
     * ==================================================*/
    irank=0;
    mpi_off = irank*DIMSIZE;
    if ((mpi_err = MPI_File_read_at(fh, mpi_off, readdata, DIMSIZE, MPI_BYTE,
	    &mpi_stat))
	    != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	PRINTID;
	printf("MPI_File_read_at offset(%ld), bytes (%d), failed (%s)\n",
		(long) mpi_off, DIMSIZE, mpi_err_str);
	return 1;
    };
    for (i=0; i < DIMSIZE; i++){
	expect_val = irank*DIMSIZE + i;
	if (readdata[i] != expect_val){
	    PRINTID;
	    printf("read data[%d:%d] got %02x, expect %02x\n", irank, i,
		    readdata[i], expect_val);
	    nerrs++;
	}
    }

    MPI_File_close(&fh);

    if (VERBOSE_HI){
	PRINTID;
	printf("%d data errors detected\n", nerrs);
    }

    mpi_err = MPI_Barrier(MPI_COMM_WORLD);
    return nerrs;
}

/*

Function: test_mpio_derived_dtype

Test Whether the Displacement of MPI derived datatype
(+ File_set_view + MPI_write)works or not on this MPI-IO package
and this platform.

1. Details for the test:
1) Create two derived datatypes with MPI_Type_hindexed:
        datatype1:
	count = 1, blocklens = 1, offsets = 0,
	base type = MPI_BYTE(essentially a char)
        datatype2:
	count = 1, blocklens = 1, offsets = 1(byte),
	base type = MPI_BYTE

2) Using these two derived datatypes,
   Build another derived datatype with MPI_Type_struct:
        advtype: derived from datatype1 and datatype2
        advtype:
	count = 2, blocklens[0] = 1, blocklens[1]=1,
	offsets[0] = 0, offsets[1] = 1(byte),
        bas_type[0]=datatype1,
        bas_type[1] = datatype2;

3) Setting MPI file view with advtype
4) Writing 2 bytes 1 to 2 using MPI_File_write to a file
5) File content:
Suppose the fill value of the file is 0(most machines indeed do so)
and Fill value is embraced with "() in the following output:
Expected output should be:
1,0,2



However, at some platforms, for example, IBM AIX(at March 23rd, 2005):
the following values were obtained:
1,2,0

The problem is that the displacement of the second derived datatype(datatype2) which formed the final derived datatype(advtype)
 has been put after the basic datatype(MPI_BYTE) of datatype2. This is a bug.


2. This test will verify whether the complicated derived datatype is working on
the current platform.

If this bug has been fixed in the previous not-working package, this test will issue a printf message to tell the developer to change
the configuration specific file of HDF5 so that we can change our configurationsetting to support collective IO for irregular selections.

If it turns out that the previous working MPI-IO package no longer works, this test will also issue a message to inform the corresponding failure so that
we can turn off collective IO support for irregular selections.
*/

static int test_mpio_derived_dtype(char *filename) {

    MPI_File fh;
    char mpi_err_str[MPI_MAX_ERROR_STRING];
    int  mpi_err_strlen;
    int  mpi_err;
    int  i;
    int  nerrors = 0;		/* number of errors */
    MPI_Datatype  etype,filetype;
    MPI_Datatype  adv_filetype,bas_filetype[2];
    MPI_Datatype  etypenew, filetypenew;
    MPI_Offset    disp;
    MPI_Status    Status;
    MPI_Aint      adv_disp[2];
    MPI_Aint      offsets[1];
    int           blocklens[1],adv_blocklens[2];
    int           count,outcount;
    int           retcode;

    int mpi_rank,mpi_size;

    char          buf[3],outbuf[3] = {0};

    MPI_Comm_size(MPI_COMM_WORLD, &mpi_size);
    MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);
    retcode = 0;
    for(i=0;i<3;i++)
      buf[i] = i+1;


    if ((mpi_err = MPI_File_open(MPI_COMM_WORLD, filename,
				 MPI_MODE_RDWR | MPI_MODE_CREATE,
				 MPI_INFO_NULL, &fh))
	    != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_open failed (%s)\n", mpi_err_str);
	return 1;
    }

    disp  = 0;
    etype = MPI_BYTE;

    count = 1;
    blocklens[0] = 1;
    offsets[0]   = 0;

    if((mpi_err= MPI_Type_hindexed(count,blocklens,offsets,MPI_BYTE,&filetype))
       != MPI_SUCCESS){
      	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_contiguous failed (%s)\n", mpi_err_str);
	return 1;
    }

    if((mpi_err=MPI_Type_commit(&filetype))!=MPI_SUCCESS){
        MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_commit failed (%s)\n", mpi_err_str);
	return 1;
    }

    count = 1;
    blocklens[0]=1;
    offsets[0] = 1;
    if((mpi_err= MPI_Type_hindexed(count,blocklens,offsets,MPI_BYTE,&filetypenew))
       != MPI_SUCCESS){
      	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_contiguous failed (%s)\n", mpi_err_str);
	return 1;
    }

    if((mpi_err=MPI_Type_commit(&filetypenew))!=MPI_SUCCESS){
        MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_commit failed (%s)\n", mpi_err_str);
	return 1;
    }

    outcount         = 2;
    adv_blocklens[0] = 1;
    adv_blocklens[1] = 1;
    adv_disp[0]      = 0;
    adv_disp[1]      = 1;
    bas_filetype[0]  = filetype;
    bas_filetype[1]  = filetypenew;

    if((mpi_err= MPI_Type_struct(outcount,adv_blocklens,adv_disp,bas_filetype,&adv_filetype))
       != MPI_SUCCESS){
      	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_struct failed (%s)\n", mpi_err_str);
	return 1;
    }
    if((mpi_err=MPI_Type_commit(&adv_filetype))!=MPI_SUCCESS){
        MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_commit failed (%s)\n", mpi_err_str);
	return 1;
    }


    if((mpi_err = MPI_File_set_view(fh,disp,etype,adv_filetype,"native",MPI_INFO_NULL))!= MPI_SUCCESS){
      MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_set_view failed (%s)\n", mpi_err_str);
	return 1;
    }

    if((mpi_err = MPI_File_write(fh,buf,3,MPI_BYTE,&Status))!= MPI_SUCCESS){
        MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_write failed (%s)\n", mpi_err_str);
	return 1;
      ;
    }


    if((mpi_err = MPI_File_close(&fh)) != MPI_SUCCESS){
       MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_close failed (%s)\n", mpi_err_str);
	return 1;
    }


    if((mpi_err = MPI_File_open(MPI_COMM_WORLD,filename,MPI_MODE_RDONLY,MPI_INFO_NULL,&fh)) != MPI_SUCCESS){
       MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_open failed (%s)\n", mpi_err_str);
	return 1;
    }

    if((mpi_err = MPI_File_set_view(fh,0,MPI_BYTE,MPI_BYTE,"native",MPI_INFO_NULL))!= MPI_SUCCESS){
        MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_set_view failed (%s)\n", mpi_err_str);
	return 1;
    }
    if((mpi_err = MPI_File_read(fh,outbuf,3,MPI_BYTE,&Status))!=MPI_SUCCESS){
      MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
      printf("MPI_File_read failed (%s)\n", mpi_err_str);
      return 1;
    }

    if(outbuf[2]==2) {
       retcode = 0;
    }
    else {
/*      if(mpi_rank == 0) {
       printf("complicated derived datatype is NOT working at this platform\n");
       printf("go back to hdf5/config and find the corresponding\n");
       printf("configure-specific file and change ?????\n");
      }
*/
       retcode = -1;
   }

    if((mpi_err = MPI_File_close(&fh)) != MPI_SUCCESS){
       MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_close failed (%s)\n", mpi_err_str);
	return 1;
    }


    mpi_err = MPI_Barrier(MPI_COMM_WORLD);
#ifdef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
    if(retcode == -1) {
	if(mpi_rank == 0) {
	    printf("Complicated derived datatype is NOT working at this platform\n");
	    printf("Go back to hdf5/config and find the corresponding\n");
	    printf("configure-specific file (for example, powerpc-ibm-aix5.x) and add\n");
	    printf("hdf5_cv_mpi_complex_derived_datatype_works=${hdf5_cv_mpi_complex_derived_datatype-works='no'}\n");
	    printf(" at the end of the file.\n");
	    printf(" Please report to hdfhelp@ncsa.uiuc.edu about this problem.\n");
	}
	retcode = 1;
    }
#else
    if(retcode == 0) {
	if(mpi_rank == 0) {
	    printf(" This is NOT an error, What it really says is\n");
	    printf("Complicated derived datatype is WORKING at this platform\n");
	    printf(" Go back to hdf5/config and find the corresponding \n");
	    printf(" configure-specific file (for example, powerpc-ibm-aix5.x) and delete the line\n");
	    printf("hdf5_cv_mpi_complex_derived_datatype_works=${hdf5_cv_mpi_complex_derived_datatype-works='no'}\n");
	    printf(" at the end of the file.\n");
	    printf("Please report to hdfhelp@ncsa.uiuc.edu about this problem.\n");
	}
	retcode = 1;
    }
    if(retcode == -1) retcode = 0;
#endif
    return retcode;
}
/*

Function: test_mpio_special_collective

Test Whether collective IO is still working when more than one process
has no contribution to IO. To properly test this case, at least FOUR
processes are needed.

1. Details for the test:
1) Create one derived datatype with MPI_Type_hindexed:

2) Choosing at least two processes to contribute none for IO with
   the buf size inside MPI_Write_at_all to 0.
3) Choosing at least two processes to have real contributions for IO.
4) Do collective IO.

2. This test will fail with the MPI-IO package that doesn't support this. For example,
mpich 1.2.6.

If this bug has been fixed in the previous not-working package, this test will issue a printf message to tell the developer to change
the configuration specific file of HDF5 so that we can change our configurationsetting to support special collective IO; currently only special collective IO.

If it turns out that the previous working MPI-IO package no longer works, this test will also issue a message to inform the corresponding failure so that
we can turn off the support for special collective IO; currently only special collective IO.
*/

static int
test_mpio_special_collective(char *filename)
{
    int  mpi_size, mpi_rank;
    MPI_File fh;
    MPI_Datatype etype,buftype,filetype;
    char mpi_err_str[MPI_MAX_ERROR_STRING];
    int  mpi_err_strlen;
    int  mpi_err;
    char writedata[2];
    char *buf;
    int  i;
    int  count,bufcount;
    int blocklens[2];
    MPI_Aint offsets[2];
    MPI_Offset  mpi_off;
    MPI_Status  mpi_stat;
    int  retcode;

    MPI_Comm_size(MPI_COMM_WORLD, &mpi_size);
    MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);
    retcode = 0;

    /* create MPI data type */
    etype = MPI_BYTE;
    if(mpi_rank == 0 || mpi_rank == 1) {
        count = DIMSIZE;
        bufcount = 1;
    }
    else {
        count = 0;
        bufcount = 0;
    }

    blocklens[0] = count;
    offsets[0] = mpi_rank*count;
    blocklens[1] = count;
    offsets[1] = (mpi_size+mpi_rank)*count;

    if(count !=0) {
      if((mpi_err= MPI_Type_hindexed(2,blocklens,offsets,etype,&filetype))
       != MPI_SUCCESS){
      	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_contiguous failed (%s)\n", mpi_err_str);
	return 1;
      }

      if((mpi_err=MPI_Type_commit(&filetype))!=MPI_SUCCESS){
        MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_commit failed (%s)\n", mpi_err_str);
	return 1;
      }


      if((mpi_err= MPI_Type_hindexed(2,blocklens,offsets,etype,&buftype))
       != MPI_SUCCESS){
      	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_contiguous failed (%s)\n", mpi_err_str);
	return 1;
      }

      if((mpi_err=MPI_Type_commit(&buftype))!=MPI_SUCCESS){
        MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_Type_commit failed (%s)\n", mpi_err_str);
	return 1;
      }
     }
     else {

       filetype = MPI_BYTE;
       buftype  = MPI_BYTE;
     }

   /* Open a file */
    if ((mpi_err = MPI_File_open(MPI_COMM_WORLD, filename,
	    MPI_MODE_RDWR | MPI_MODE_CREATE ,
	    MPI_INFO_NULL, &fh))
	    != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_open failed (%s)\n", mpi_err_str);
	return 1;
    }

    /* each process writes some data */
    for (i=0; i < 2*DIMSIZE; i++)
	writedata[i] = mpi_rank*DIMSIZE + i;


     mpi_off = 0;
    if((mpi_err = MPI_File_set_view(fh, mpi_off, MPI_BYTE, filetype, "native", MPI_INFO_NULL))
        != MPI_SUCCESS) {
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_set_view failed (%s)\n", mpi_err_str);
	return 1;
    }

    buf   = writedata;
    if ((mpi_err = MPI_File_write_at_all(fh, mpi_off, buf, bufcount, buftype,
	    &mpi_stat))
	    != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_write_at offset(%ld), bytes (%d), failed (%s)\n",
		(long) mpi_off, bufcount, mpi_err_str);
	return 1;
    };

     if ((mpi_err = MPI_File_close(&fh))
	    != MPI_SUCCESS){
	MPI_Error_string(mpi_err, mpi_err_str, &mpi_err_strlen);
	printf("MPI_File_close failed. \n");
	return 1;
    };

    mpi_err = MPI_Barrier(MPI_COMM_WORLD);
#ifdef H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS
    if(retcode != 0) {
	if(mpi_rank == 0) {
	    printf("special collective IO is NOT working at this platform\n");
	    printf("Go back to hdf5/config and find the corresponding\n");
	    printf("configure-specific file (for example, powerpc-ibm-aix5.x) and add\n");
	    printf("hdf5_cv_mpi_special_collective_io_works=${hdf5_cv_mpi_special_collective_io_works='no'}\n");
	    printf(" at the end of the file.\n");
	    printf(" Please report to hdfhelp@ncsa.uiuc.edu about this problem.\n");
	}
	retcode = 1;
    }
#else
    if(retcode == 0) {
	if(mpi_rank == 0) {
	    printf(" This is NOT an error, What it really says is\n");
	    printf("special collective IO is WORKING at this platform\n");
	    printf(" Go back to hdf5/config and find the corresponding \n");
	    printf(" configure-specific file (for example, powerpc-ibm-aix5.x) and delete the line\n");
	    printf("hdf5_cv_mpi_special_collective_io_works=${hdf5_cv_mpi_special_collective_io_works='no'}\n");
	    printf(" at the end of the file.\n");
	    printf("Please report to hdfhelp@ncsa.uiuc.edu about this problem.\n");
	}
	retcode = 1;
    }
#endif
    return retcode;
}

/*
 * parse the command line options
 */
static int
parse_options(int argc, char **argv)
{
    while (--argc){
	if (**(++argv) != '-'){
	    break;
	}else{
	    switch(*(*argv+1)){
		case 'v':   if (*((*argv+1)+1))
				ParseTestVerbosity((*argv+1)+1);
			    else
				SetTestVerbosity(VERBO_MED);
			    break;
		case 'f':   if (--argc < 1) {
				nerrors++;
				return(1);
			    }
			    if (**(++argv) == '-') {
				nerrors++;
				return(1);
			    }
			    paraprefix = *argv;
			    break;
		case 'h':   /* print help message--return with nerrors set */
			    return(1);
		default:    nerrors++;
			    return(1);
	    }
	}
    } /*while*/

    /* compose the test filenames */
    {
	int i, n;
	hid_t plist;

	plist = H5Pcreate (H5P_FILE_ACCESS);
	H5Pset_fapl_mpio(plist, MPI_COMM_WORLD, MPI_INFO_NULL);
	n = sizeof(FILENAME)/sizeof(FILENAME[0]) - 1;	/* exclude the NULL */

	for (i=0; i < n; i++)
	    if (h5_fixname(FILENAME[i],plist,filenames[i],sizeof(filenames[i]))
		== NULL){
		printf("h5_fixname failed\n");
		nerrors++;
		return(1);
	    }
	H5Pclose(plist);
	if (VERBOSE_MED){
	    printf("Test filenames are:\n");
	    for (i=0; i < n; i++)
		printf("    %s\n", filenames[i]);
	}
    }

    return(0);
}


/*
 * Show command usage
 */
static void
usage(void)
{
    printf("Usage: t_mpi [-v<verbosity>] [-f <prefix>]\n");
    printf("\t-v<verbosity>\tset verbose level (0-9,l,m,h)\n");
    printf("\t-f <prefix>\tfilename prefix\n");
    printf("\n");
}

/*
 * return the sum of all errors.
 */
static int
errors_sum(int nerrs)
{
    int temp;
    MPI_Allreduce(&nerrs, &temp, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
    return(temp);
}


int
main(int argc, char **argv)
{
    int mpi_size, mpi_rank;				/* mpi variables */
    int ret_code;

    MPI_Init(&argc, &argv);
    MPI_Comm_size(MPI_COMM_WORLD, &mpi_size);
    MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);

    H5open();
    if (parse_options(argc, argv) != 0){
	if (MAINPROCESS)
	    usage();
	goto finish;
    }

    if (MAINPROCESS){
	printf("===================================\n");
	printf("MPI functionality tests\n");
	printf("===================================\n");
    }

    if (VERBOSE_MED)
	h5_show_hostname();

    fapl = H5Pcreate (H5P_FILE_ACCESS);
    H5Pset_fapl_mpio(fapl, MPI_COMM_WORLD, MPI_INFO_NULL);

    /* set alarm. */
    ALARM_ON;


    /*=======================================
     * MPIO 1 write Many read test
     *=======================================*/
    MPI_BANNER("MPIO 1 write Many read test...");
    ret_code = test_mpio_1wMr(filenames[0], USENONE);
    ret_code = errors_sum(ret_code);
    if (mpi_rank==0 && ret_code > 0){
	printf("***FAILED with %d total errors\n", ret_code);
	nerrors += ret_code;
    }

    /* test atomicity and file sync in high verbose mode only         */
    /* since they often hang when broken and PHDF5 does not use them. */
    if (VERBOSE_HI){
	MPI_BANNER("MPIO 1 write Many read test with atomicity...");
	ret_code = test_mpio_1wMr(filenames[0], USEATOM);
	ret_code = errors_sum(ret_code);
	if (mpi_rank==0 && ret_code > 0){
	    printf("***FAILED with %d total errors\n", ret_code);
	    nerrors += ret_code;
	}

	MPI_BANNER("MPIO 1 write Many read test with file sync...");
	ret_code = test_mpio_1wMr(filenames[0], USEFSYNC);
	ret_code = errors_sum(ret_code);
	if (mpi_rank==0 && ret_code > 0){
	    printf("***FAILED with %d total errors\n", ret_code);
	    nerrors += ret_code;
	}
    }


    /*=======================================
     * MPIO MPIO File size range test
     *=======================================*/
    MPI_BANNER("MPIO File size range test...");
    ret_code = test_mpio_gb_file(filenames[0]);
    ret_code = errors_sum(ret_code);
    if (mpi_rank==0 && ret_code > 0){
	printf("***FAILED with %d total errors\n", ret_code);
	nerrors += ret_code;
    }


    /*=======================================
     * MPIO independent overlapping writes
     *=======================================*/
    MPI_BANNER("MPIO independent overlapping writes...");
    ret_code = test_mpio_overlap_writes(filenames[0]);
    ret_code = errors_sum(ret_code);
    if (mpi_rank==0 && ret_code > 0){
	printf("***FAILED with %d total errors\n", ret_code);
	nerrors += ret_code;
    }

    /*=======================================
     * MPIO complicated derived datatype test
     *=======================================*/
    /* test_mpio_derived_dtype often hangs when fails.
     * Do not run it if it is known NOT working unless ask to
     * run explicitly by high verbose mode.
     */
#ifdef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
    MPI_BANNER("MPIO complicated derived datatype test...");
    ret_code = test_mpio_derived_dtype(filenames[0]);
#else
    if (VERBOSE_HI){
	MPI_BANNER("MPIO complicated derived datatype test...");
	ret_code = test_mpio_derived_dtype(filenames[0]);
    }else{
	MPI_BANNER("MPIO complicated derived datatype test SKIPPED.");
	ret_code = 0;	/* fake ret_code */
    }
#endif
    ret_code = errors_sum(ret_code);
    if (mpi_rank==0 && ret_code > 0){
	printf("***FAILED with %d total errors\n", ret_code);
	nerrors += ret_code;
    }

    /*=======================================
     * MPIO special collective IO  test
     *=======================================*/
    /* test_special_collective_io  often hangs when fails.
     * Do not run it if it is known NOT working unless ask to
     * run explicitly by high verbose mode.
     */
    if(mpi_size !=4){
      MPI_BANNER("MPIO special collective io test SKIPPED.");
      if(mpi_rank == 0){
        printf("Use FOUR processes to run this test\n");
        printf("If you still see the <test SKIPPED>, use <-vh> option to verify the test\n");
  }
      ret_code = 0;
      goto sc_finish;
    }

#ifdef H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS
    MPI_BANNER("MPIO special collective io test...");
    ret_code = test_mpio_special_collective(filenames[0]);

#else
    if (VERBOSE_HI){
	MPI_BANNER("MPIO special collective io test...");
	ret_code = test_mpio_special_collective(filenames[0]);
    }else{
	MPI_BANNER("MPIO special collective io test SKIPPED.");
	ret_code = 0;	/* fake ret_code */
    }
#endif

sc_finish:
    ret_code = errors_sum(ret_code);
    if (mpi_rank==0 && ret_code > 0){
	printf("***FAILED with %d total errors\n", ret_code);
	nerrors += ret_code;
    }


finish:
    /* make sure all processes are finished before final report, cleanup
     * and exit.
     */
    MPI_Barrier(MPI_COMM_WORLD);
    if (MAINPROCESS){		/* only process 0 reports */
	printf("===================================\n");
	if (nerrors){
	    printf("***MPI tests detected %d errors***\n", nerrors);
	}
	else{
	    printf("MPI tests finished with no errors\n");
	}
	printf("===================================\n");
    }

    /* turn off alarm */
    ALARM_OFF;

    h5_cleanup(FILENAME, fapl);
    H5close();

    /* MPI_Finalize must be called AFTER H5close which may use MPI calls */
    MPI_Finalize();

    /* cannot just return (nerrors) because exit code is limited to 1byte */
    return(nerrors!=0);
}