summaryrefslogtreecommitdiffstats
path: root/src/H5FDstdio.c
blob: 22d6323b84af7b782ab6fa74ea0bf307b7e58dcb (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
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
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
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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 COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://www.hdfgroup.org/licenses.               *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/* Programmer:  Robb Matzke
 *              Wednesday, October 22, 1997
 *
 * Purpose: The C STDIO virtual file driver which only uses calls from stdio.h.
 *          This also serves as an example of coding a simple file driver,
 *          therefore, it should not use any non-public definitions.
 *
 * NOTE:    This driver is not as well tested as the standard SEC2 driver
 *          and is not intended for production use!
 */
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

#include "hdf5.h"

#ifdef H5_HAVE_FLOCK
/* Needed for lock type definitions (e.g., LOCK_EX) */
#include <sys/file.h>
#endif /* H5_HAVE_FLOCK */

#ifdef H5_HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef H5_HAVE_WIN32_API
/* The following two defines must be before any windows headers are included */
#define WIN32_LEAN_AND_MEAN /* Exclude rarely-used stuff from Windows headers */
#define NOGDI               /* Exclude Graphic Display Interface macros */

#include <windows.h>
#include <io.h>

#endif /* H5_HAVE_WIN32_API */

/* The driver identification number, initialized at runtime */
static hid_t H5FD_STDIO_g = 0;

/* Whether to ignore file locks when disabled (env var value) */
static htri_t ignore_disabled_file_locks_s = -1;

/* The maximum number of bytes which can be written in a single I/O operation */
static size_t H5_STDIO_MAX_IO_BYTES_g = (size_t)-1;

/* File operations */
typedef enum {
    H5FD_STDIO_OP_UNKNOWN = 0,
    H5FD_STDIO_OP_READ    = 1,
    H5FD_STDIO_OP_WRITE   = 2,
    H5FD_STDIO_OP_SEEK    = 3
} H5FD_stdio_file_op;

/* The description of a file belonging to this driver. The 'eoa' and 'eof'
 * determine the amount of hdf5 address space in use and the high-water mark
 * of the file (the current size of the underlying Unix file). The 'pos'
 * value is used to eliminate file position updates when they would be a
 * no-op. Unfortunately we've found systems that use separate file position
 * indicators for reading and writing so the lseek can only be eliminated if
 * the current operation is the same as the previous operation.  When opening
 * a file the 'eof' will be set to the current file size, 'eoa' will be set
 * to zero, 'pos' will be set to H5F_ADDR_UNDEF (as it is when an error
 * occurs), and 'op' will be set to H5F_OP_UNKNOWN.
 */
typedef struct H5FD_stdio_t {
    H5FD_t             pub;          /* public stuff, must be first      */
    FILE *             fp;           /* the file handle                  */
    int                fd;           /* file descriptor (for truncate)   */
    haddr_t            eoa;          /* end of allocated region          */
    haddr_t            eof;          /* end of file; current file size   */
    haddr_t            pos;          /* current file I/O position        */
    unsigned           write_access; /* Flag to indicate the file was opened with write access */
    hbool_t            ignore_disabled_file_locks;
    H5FD_stdio_file_op op; /* last operation */
#ifndef H5_HAVE_WIN32_API
    /* On most systems the combination of device and i-node number uniquely
     * identify a file.  Note that Cygwin, MinGW and other Windows POSIX
     * environments have the stat function (which fakes inodes)
     * and will use the 'device + inodes' scheme as opposed to the
     * Windows code further below.
     */
    dev_t device; /* file device number   */
    ino_t inode;  /* file i-node number   */
#else
    /* Files in windows are uniquely identified by the volume serial
     * number and the file index (both low and high parts).
     *
     * There are caveats where these numbers can change, especially
     * on FAT file systems.  On NTFS, however, a file should keep
     * those numbers the same until renamed or deleted (though you
     * can use ReplaceFile() on NTFS to keep the numbers the same
     * while renaming).
     *
     * See the MSDN "BY_HANDLE_FILE_INFORMATION Structure" entry for
     * more information.
     *
     * http://msdn.microsoft.com/en-us/library/aa363788(v=VS.85).aspx
     */
    DWORD nFileIndexLow;
    DWORD nFileIndexHigh;
    DWORD dwVolumeSerialNumber;

    HANDLE      hFile; /* Native windows file handle */
#endif /* H5_HAVE_WIN32_API */
} H5FD_stdio_t;

/* Use similar structure as in H5private.h by defining Windows stuff first. */
#ifdef H5_HAVE_WIN32_API
#ifndef H5_HAVE_MINGW
#define file_fseek     _fseeki64
#define file_offset_t  __int64
#define file_ftruncate _chsize_s /* Supported in VS 2005 or newer */
#define file_ftell     _ftelli64
#endif /* H5_HAVE_MINGW */
#endif /* H5_HAVE_WIN32_API */

/* If these functions weren't re-defined for Windows, give them
 * more platform-independent names.
 */
#ifndef file_fseek
#define file_fseek     fseeko
#define file_offset_t  off_t
#define file_ftruncate ftruncate
#define file_ftell     ftello
#endif /* file_fseek */

/* These macros check for overflow of various quantities.  These macros
 * assume that file_offset_t is signed and haddr_t and size_t are unsigned.
 *
 * ADDR_OVERFLOW:  Checks whether a file address of type `haddr_t'
 *      is too large to be represented by the second argument
 *      of the file seek function.
 *
 * SIZE_OVERFLOW:  Checks whether a buffer size of type `hsize_t' is too
 *      large to be represented by the `size_t' type.
 *
 * REGION_OVERFLOW:  Checks whether an address and size pair describe data
 *      which can be addressed entirely by the second
 *      argument of the file seek function.
 */
/* adding for windows NT filesystem support. */
#define MAXADDR          (((haddr_t)1 << (8 * sizeof(file_offset_t) - 1)) - 1)
#define ADDR_OVERFLOW(A) (HADDR_UNDEF == (A) || ((A) & ~(haddr_t)MAXADDR))
#define SIZE_OVERFLOW(Z) ((Z) & ~(hsize_t)MAXADDR)
#define REGION_OVERFLOW(A, Z)                                                                                \
    (ADDR_OVERFLOW(A) || SIZE_OVERFLOW(Z) || HADDR_UNDEF == (A) + (Z) ||                                     \
     (file_offset_t)((A) + (Z)) < (file_offset_t)(A))

/* Prototypes */
static herr_t  H5FD_stdio_term(void);
static H5FD_t *H5FD_stdio_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr);
static herr_t  H5FD_stdio_close(H5FD_t *lf);
static int     H5FD_stdio_cmp(const H5FD_t *_f1, const H5FD_t *_f2);
static herr_t  H5FD_stdio_query(const H5FD_t *_f1, unsigned long *flags);
static haddr_t H5FD_stdio_alloc(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, hsize_t size);
static haddr_t H5FD_stdio_get_eoa(const H5FD_t *_file, H5FD_mem_t type);
static herr_t  H5FD_stdio_set_eoa(H5FD_t *_file, H5FD_mem_t type, haddr_t addr);
static haddr_t H5FD_stdio_get_eof(const H5FD_t *_file, H5FD_mem_t type);
static herr_t  H5FD_stdio_get_handle(H5FD_t *_file, hid_t fapl, void **file_handle);
static herr_t  H5FD_stdio_read(H5FD_t *lf, H5FD_mem_t type, hid_t fapl_id, haddr_t addr, size_t size,
                               void *buf);
static herr_t  H5FD_stdio_write(H5FD_t *lf, H5FD_mem_t type, hid_t fapl_id, haddr_t addr, size_t size,
                                const void *buf);
static herr_t  H5FD_stdio_flush(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);
static herr_t  H5FD_stdio_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);
static herr_t  H5FD_stdio_lock(H5FD_t *_file, hbool_t rw);
static herr_t  H5FD_stdio_unlock(H5FD_t *_file);
static herr_t  H5FD_stdio_delete(const char *filename, hid_t fapl_id);

static const H5FD_class_t H5FD_stdio_g = {
    H5_VFD_STDIO,          /* value        */
    "stdio",               /* name         */
    MAXADDR,               /* maxaddr      */
    H5F_CLOSE_WEAK,        /* fc_degree    */
    H5FD_stdio_term,       /* terminate    */
    NULL,                  /* sb_size      */
    NULL,                  /* sb_encode    */
    NULL,                  /* sb_decode    */
    0,                     /* fapl_size    */
    NULL,                  /* fapl_get     */
    NULL,                  /* fapl_copy    */
    NULL,                  /* fapl_free    */
    0,                     /* dxpl_size    */
    NULL,                  /* dxpl_copy    */
    NULL,                  /* dxpl_free    */
    H5FD_stdio_open,       /* open         */
    H5FD_stdio_close,      /* close        */
    H5FD_stdio_cmp,        /* cmp          */
    H5FD_stdio_query,      /* query        */
    NULL,                  /* get_type_map */
    H5FD_stdio_alloc,      /* alloc        */
    NULL,                  /* free         */
    H5FD_stdio_get_eoa,    /* get_eoa      */
    H5FD_stdio_set_eoa,    /* set_eoa      */
    H5FD_stdio_get_eof,    /* get_eof      */
    H5FD_stdio_get_handle, /* get_handle   */
    H5FD_stdio_read,       /* read         */
    H5FD_stdio_write,      /* write        */
    NULL,                  /* read_vector  */
    NULL,                  /* write_vector */
    NULL,                  /* read_selection  */
    NULL,                  /* write_selection */
    H5FD_stdio_flush,      /* flush        */
    H5FD_stdio_truncate,   /* truncate     */
    H5FD_stdio_lock,       /* lock         */
    H5FD_stdio_unlock,     /* unlock       */
    H5FD_stdio_delete,     /* del          */
    NULL,                  /* ctl          */
    H5FD_FLMAP_DICHOTOMY   /* fl_map       */
};

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_init
 *
 * Purpose:  Initialize this driver by registering the driver with the
 *    library.
 *
 * Return:  Success:  The driver ID for the stdio driver.
 *
 *    Failure:  Negative.
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5FD_stdio_init(void)
{
    char *lock_env_var = NULL; /* Environment variable pointer */

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Check the use disabled file locks environment variable */
    lock_env_var = getenv(HDF5_USE_FILE_LOCKING);
    if (lock_env_var && !strcmp(lock_env_var, "BEST_EFFORT"))
        ignore_disabled_file_locks_s = 1; /* Override: Ignore disabled locks */
    else if (lock_env_var && (!strcmp(lock_env_var, "TRUE") || !strcmp(lock_env_var, "1")))
        ignore_disabled_file_locks_s = 0; /* Override: Don't ignore disabled locks */
    else
        ignore_disabled_file_locks_s = -1; /* Environment variable not set, or not set correctly */

    if (H5I_VFL != H5Iget_type(H5FD_STDIO_g))
        H5FD_STDIO_g = H5FDregister(&H5FD_stdio_g);

    return H5FD_STDIO_g;
} /* end H5FD_stdio_init() */

/*---------------------------------------------------------------------------
 * Function:  H5FD_stdio_term
 *
 * Purpose:  Shut down the VFD
 *
 * Returns:     Non-negative on success or negative on failure
 *
 * Programmer:  Quincey Koziol
 *              Friday, Jan 30, 2004
 *
 *---------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_term(void)
{
    /* Reset VFL ID */
    H5FD_STDIO_g = 0;

    return 0;
} /* end H5FD_stdio_term() */

/*-------------------------------------------------------------------------
 * Function:  H5Pset_fapl_stdio
 *
 * Purpose:  Modify the file access property list to use the H5FD_STDIO
 *    driver defined in this source file.  There are no driver
 *    specific properties.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Robb Matzke
 *    Thursday, February 19, 1998
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_fapl_stdio(hid_t fapl_id)
{
    static const char *func = "H5FDset_fapl_stdio"; /*for error reporting*/

    /*NO TRACE*/

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    if (0 == H5Pisa_class(fapl_id, H5P_FILE_ACCESS))
        H5Epush_ret(func, H5E_ERR_CLS, H5E_PLIST, H5E_BADTYPE, "not a file access property list", -1);

    return H5Pset_driver(fapl_id, H5FD_STDIO, NULL);
} /* end H5Pset_fapl_stdio() */

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_open
 *
 * Purpose:  Create and/or opens a Standard C file as an HDF5 file.
 *
 * Errors:
 *  IO  CANTOPENFILE    File doesn't exist and CREAT wasn't
 *                      specified.
 *  IO  CANTOPENFILE    fopen() failed.
 *  IO  FILEEXISTS      File exists but CREAT and EXCL were
 *                      specified.
 *
 * Return:
 *      Success:    A pointer to a new file data structure. The
 *                  public fields will be initialized by the
 *                  caller, which is always H5FD_open().
 *
 *      Failure:    NULL
 *
 * Programmer:  Robb Matzke
 *    Wednesday, October 22, 1997
 *
 *-------------------------------------------------------------------------
 */
static H5FD_t *
H5FD_stdio_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
{
    FILE *             f            = NULL;
    unsigned           write_access = 0; /* File opened with write access? */
    H5FD_stdio_t *     file         = NULL;
    static const char *func         = "H5FD_stdio_open"; /* Function Name for error reporting */
#ifdef H5_HAVE_WIN32_API
    struct _BY_HANDLE_FILE_INFORMATION fileinfo;
#else  /* H5_HAVE_WIN32_API */
    struct stat sb;
#endif /* H5_HAVE_WIN32_API */

    /* Sanity check on file offsets */
    assert(sizeof(file_offset_t) >= sizeof(size_t));

    /* Quiet compiler */
    (void)fapl_id;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Check arguments */
    if (!name || !*name)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_ARGS, H5E_BADVALUE, "invalid file name", NULL);
    if (0 == maxaddr || HADDR_UNDEF == maxaddr)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_ARGS, H5E_BADRANGE, "bogus maxaddr", NULL);
    if (ADDR_OVERFLOW(maxaddr))
        H5Epush_ret(func, H5E_ERR_CLS, H5E_ARGS, H5E_OVERFLOW, "maxaddr too large", NULL);

    /* Tentatively open file in read-only mode, to check for existence */
    if (flags & H5F_ACC_RDWR)
        f = fopen(name, "rb+");
    else
        f = fopen(name, "rb");

    if (!f) {
        /* File doesn't exist */
        if (flags & H5F_ACC_CREAT) {
            assert(flags & H5F_ACC_RDWR);
            f            = fopen(name, "wb+");
            write_access = 1; /* Note the write access */
        }
        else
            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_CANTOPENFILE,
                        "file doesn't exist and CREAT wasn't specified", NULL);
    }
    else if (flags & H5F_ACC_EXCL) {
        /* File exists, but EXCL is passed.  Fail. */
        assert(flags & H5F_ACC_CREAT);
        fclose(f);
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_FILEEXISTS,
                    "file exists but CREAT and EXCL were specified", NULL);
    }
    else if (flags & H5F_ACC_RDWR) {
        if (flags & H5F_ACC_TRUNC)
            f = freopen(name, "wb+", f);
        write_access = 1; /* Note the write access */
    }                     /* end if */
    /* Note there is no need to reopen if neither TRUNC nor EXCL are specified,
     * as the tentative open will work */

    if (!f)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_CANTOPENFILE, "fopen failed", NULL);

    /* Build the return value */
    if (NULL == (file = (H5FD_stdio_t *)calloc((size_t)1, sizeof(H5FD_stdio_t)))) {
        fclose(f);
        H5Epush_ret(func, H5E_ERR_CLS, H5E_RESOURCE, H5E_NOSPACE, "memory allocation failed", NULL);
    } /* end if */
    file->fp           = f;
    file->op           = H5FD_STDIO_OP_SEEK;
    file->pos          = HADDR_UNDEF;
    file->write_access = write_access; /* Note the write_access for later */
    if (file_fseek(file->fp, (file_offset_t)0, SEEK_END) < 0) {
        file->op = H5FD_STDIO_OP_UNKNOWN;
    }
    else {
        file_offset_t x = file_ftell(file->fp);
        assert(x >= 0);
        file->eof = (haddr_t)x;
    }

    /* Check the file locking flags in the fapl */
    if (ignore_disabled_file_locks_s != -1)
        /* The environment variable was set, so use that preferentially */
        file->ignore_disabled_file_locks = ignore_disabled_file_locks_s;
    else {
        hbool_t unused;

        /* Use the value in the property list */
        if (H5Pget_file_locking(fapl_id, &unused, &file->ignore_disabled_file_locks) < 0) {
            free(file);
            fclose(f);
            H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_CANTGET,
                        "unable to get use disabled file locks property", NULL);
        }
    }

    /* Get the file descriptor (needed for truncate and some Windows information) */
#ifdef H5_HAVE_WIN32_API
    file->fd = _fileno(file->fp);
#else  /* H5_HAVE_WIN32_API */
    file->fd = fileno(file->fp);
#endif /* H5_HAVE_WIN32_API */
    if (file->fd < 0) {
        free(file);
        fclose(f);
        H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_CANTOPENFILE, "unable to get file descriptor", NULL);
    } /* end if */

#ifdef H5_HAVE_WIN32_API
    file->hFile = (HANDLE)_get_osfhandle(file->fd);
    if (INVALID_HANDLE_VALUE == file->hFile) {
        free(file);
        fclose(f);
        H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_CANTOPENFILE, "unable to get Windows file handle", NULL);
    } /* end if */

    if (!GetFileInformationByHandle((HANDLE)file->hFile, &fileinfo)) {
        free(file);
        fclose(f);
        H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_CANTOPENFILE,
                    "unable to get Windows file descriptor information", NULL);
    } /* end if */

    file->nFileIndexHigh       = fileinfo.nFileIndexHigh;
    file->nFileIndexLow        = fileinfo.nFileIndexLow;
    file->dwVolumeSerialNumber = fileinfo.dwVolumeSerialNumber;
#else  /* H5_HAVE_WIN32_API */
    if (fstat(file->fd, &sb) < 0) {
        free(file);
        fclose(f);
        H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_BADFILE, "unable to fstat file", NULL);
    } /* end if */
    file->device = sb.st_dev;
    file->inode  = sb.st_ino;
#endif /* H5_HAVE_WIN32_API */

    return ((H5FD_t *)file);
} /* end H5FD_stdio_open() */

/*-------------------------------------------------------------------------
 * Function:  H5F_stdio_close
 *
 * Purpose:  Closes a file.
 *
 * Errors:
 *    IO    CLOSEERROR  Fclose failed.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Robb Matzke
 *    Wednesday, October 22, 1997
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_close(H5FD_t *_file)
{
    H5FD_stdio_t *     file = (H5FD_stdio_t *)_file;
    static const char *func = "H5FD_stdio_close"; /* Function Name for error reporting */

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    if (fclose(file->fp) < 0)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_CLOSEERROR, "fclose failed", -1);

    free(file);

    return 0;
} /* end H5FD_stdio_close() */

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_cmp
 *
 * Purpose:  Compares two files belonging to this driver using an
 *    arbitrary (but consistent) ordering.
 *
 * Return:
 *      Success:    A value like strcmp()
 *
 *      Failure:    never fails (arguments were checked by the caller).
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static int
H5FD_stdio_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
{
    const H5FD_stdio_t *f1 = (const H5FD_stdio_t *)_f1;
    const H5FD_stdio_t *f2 = (const H5FD_stdio_t *)_f2;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

#ifdef H5_HAVE_WIN32_API
    if (f1->dwVolumeSerialNumber < f2->dwVolumeSerialNumber)
        return -1;
    if (f1->dwVolumeSerialNumber > f2->dwVolumeSerialNumber)
        return 1;

    if (f1->nFileIndexHigh < f2->nFileIndexHigh)
        return -1;
    if (f1->nFileIndexHigh > f2->nFileIndexHigh)
        return 1;

    if (f1->nFileIndexLow < f2->nFileIndexLow)
        return -1;
    if (f1->nFileIndexLow > f2->nFileIndexLow)
        return 1;
#else /* H5_HAVE_WIN32_API */
#ifdef H5_DEV_T_IS_SCALAR
    if (f1->device < f2->device)
        return -1;
    if (f1->device > f2->device)
        return 1;
#else  /* H5_DEV_T_IS_SCALAR */
    /* If dev_t isn't a scalar value on this system, just use memcmp to
     * determine if the values are the same or not.  The actual return value
     * shouldn't really matter...
     */
    if (memcmp(&(f1->device), &(f2->device), sizeof(dev_t)) < 0)
        return -1;
    if (memcmp(&(f1->device), &(f2->device), sizeof(dev_t)) > 0)
        return 1;
#endif /* H5_DEV_T_IS_SCALAR */
    if (f1->inode < f2->inode)
        return -1;
    if (f1->inode > f2->inode)
        return 1;
#endif /* H5_HAVE_WIN32_API */

    return 0;
} /* H5FD_stdio_cmp() */

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_query
 *
 * Purpose:  Set the flags that this VFL driver is capable of supporting.
 *              (listed in H5FDpublic.h)
 *
 * Return:  Success:  non-negative
 *
 *    Failure:  negative
 *
 * Programmer:  Quincey Koziol
 *              Friday, August 25, 2000
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_query(const H5FD_t *_f, unsigned long /*OUT*/ *flags)
{
    /* Quiet the compiler */
    (void)_f;

    /* Set the VFL feature flags that this driver supports.
     *
     * Note that this VFD does not support SWMR due to the unpredictable
     * nature of the buffering layer.
     */
    if (flags) {
        *flags = 0;
        *flags |= H5FD_FEAT_AGGREGATE_METADATA;  /* OK to aggregate metadata allocations  */
        *flags |= H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
        *flags |= H5FD_FEAT_DATA_SIEVE; /* OK to perform data sieving for faster raw data reads & writes    */
        *flags |= H5FD_FEAT_AGGREGATE_SMALLDATA;    /* OK to aggregate "small" raw data allocations    */
        *flags |= H5FD_FEAT_DEFAULT_VFD_COMPATIBLE; /* VFD creates a file which can be opened with the default
                                                       VFD      */
    }

    return 0;
} /* end H5FD_stdio_query() */

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_alloc
 *
 * Purpose:     Allocates file memory. If fseeko isn't available, makes
 *              sure the file size isn't bigger than 2GB because the
 *              parameter OFFSET of fseek is of the type LONG INT, limiting
 *              the file size to 2GB.
 *
 * Return:
 *      Success:    Address of new memory
 *
 *      Failure:    HADDR_UNDEF
 *
 * Programmer:  Raymond Lu
 *              30 March 2007
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_stdio_alloc(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, hid_t /*UNUSED*/ dxpl_id, hsize_t size)
{
    H5FD_stdio_t *file = (H5FD_stdio_t *)_file;
    haddr_t       addr;

    /* Quiet compiler */
    (void)type;
    (void)dxpl_id;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Compute the address for the block to allocate */
    addr = file->eoa;

    file->eoa = addr + size;

    return addr;
} /* end H5FD_stdio_alloc() */

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_get_eoa
 *
 * Purpose:  Gets the end-of-address marker for the file. The EOA marker
 *           is the first address past the last byte allocated in the
 *           format address space.
 *
 * Return:  Success:  The end-of-address marker.
 *
 *    Failure:  HADDR_UNDEF
 *
 * Programmer:  Robb Matzke
 *              Monday, August  2, 1999
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_stdio_get_eoa(const H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type)
{
    const H5FD_stdio_t *file = (const H5FD_stdio_t *)_file;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Quiet compiler */
    (void)type;

    return file->eoa;
} /* end H5FD_stdio_get_eoa() */

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_set_eoa
 *
 * Purpose:  Set the end-of-address marker for the file. This function is
 *    called shortly after an existing HDF5 file is opened in order
 *    to tell the driver where the end of the HDF5 data is located.
 *
 * Return:  Success:  0
 *
 *    Failure:  Does not fail
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_set_eoa(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, haddr_t addr)
{
    H5FD_stdio_t *file = (H5FD_stdio_t *)_file;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Quiet the compiler */
    (void)type;

    file->eoa = addr;

    return 0;
}

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_get_eof
 *
 * Purpose:  Returns the end-of-file marker, which is the greater of
 *    either the Unix end-of-file or the HDF5 end-of-address
 *    markers.
 *
 * Return:  Success:  End of file address, the first address past
 *        the end of the "file", either the Unix file
 *        or the HDF5 file.
 *
 *    Failure:  HADDR_UNDEF
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_stdio_get_eof(const H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type)
{
    const H5FD_stdio_t *file = (const H5FD_stdio_t *)_file;

    /* Quiet the compiler */
    (void)type;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Quiet the compiler */
    (void)type;

    return (file->eof);
} /* end H5FD_stdio_get_eof() */

/*-------------------------------------------------------------------------
 * Function:       H5FD_stdio_get_handle
 *
 * Purpose:        Returns the file handle of stdio file driver.
 *
 * Returns:        Non-negative if succeed or negative if fails.
 *
 * Programmer:     Raymond Lu
 *                 Sept. 16, 2002
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_get_handle(H5FD_t *_file, hid_t /*UNUSED*/ fapl, void **file_handle)
{
    H5FD_stdio_t *     file = (H5FD_stdio_t *)_file;
    static const char *func = "H5FD_stdio_get_handle"; /* Function Name for error reporting */

    /* Quiet the compiler */
    (void)fapl;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    *file_handle = &(file->fp);
    if (*file_handle == NULL)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "get handle failed", -1);

    return 0;
} /* end H5FD_stdio_get_handle() */

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_read
 *
 * Purpose:  Reads SIZE bytes beginning at address ADDR in file LF and
 *    places them in buffer BUF.  Reading past the logical or
 *    physical end of file returns zeros instead of failing.
 *
 * Errors:
 *    IO    READERROR  fread failed.
 *    IO    SEEKERROR  fseek failed.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Robb Matzke
 *    Wednesday, October 22, 1997
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_read(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, hid_t /*UNUSED*/ dxpl_id, haddr_t addr,
                size_t size, void /*OUT*/ *buf)
{
    H5FD_stdio_t *     file = (H5FD_stdio_t *)_file;
    static const char *func = "H5FD_stdio_read"; /* Function Name for error reporting */

    /* Quiet the compiler */
    (void)type;
    (void)dxpl_id;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Check for overflow */
    if (HADDR_UNDEF == addr)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1);
    if (REGION_OVERFLOW(addr, size))
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1);

    /* Check easy cases */
    if (0 == size)
        return 0;
    if ((haddr_t)addr >= file->eof) {
        memset(buf, 0, size);
        return 0;
    }

    /* Seek to the correct file position. */
    if (!(file->op == H5FD_STDIO_OP_READ || file->op == H5FD_STDIO_OP_SEEK) || file->pos != addr) {
        if (file_fseek(file->fp, (file_offset_t)addr, SEEK_SET) < 0) {
            file->op  = H5FD_STDIO_OP_UNKNOWN;
            file->pos = HADDR_UNDEF;
            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "fseek failed", -1);
        }
        file->pos = addr;
    }

    /* Read zeros past the logical end of file (physical is handled below) */
    if (addr + size > file->eof) {
        size_t nbytes = (size_t)(addr + size - file->eof);
        memset((unsigned char *)buf + size - nbytes, 0, nbytes);
        size -= nbytes;
    }

    /* Read the data.  Since we're reading single-byte values, a partial read
     * will advance the file position by N.  If N is zero or an error
     * occurs then the file position is undefined.
     */
    while (size > 0) {

        size_t bytes_in   = 0; /* # of bytes to read       */
        size_t bytes_read = 0; /* # of bytes actually read */
        size_t item_size  = 1; /* size of items in bytes */

        if (size > H5_STDIO_MAX_IO_BYTES_g)
            bytes_in = H5_STDIO_MAX_IO_BYTES_g;
        else
            bytes_in = size;

        bytes_read = fread(buf, item_size, bytes_in, file->fp);

        if (0 == bytes_read && ferror(file->fp)) { /* error */
            file->op  = H5FD_STDIO_OP_UNKNOWN;
            file->pos = HADDR_UNDEF;
            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_READERROR, "fread failed", -1);
        } /* end if */

        if (0 == bytes_read && feof(file->fp)) {
            /* end of file but not end of format address space */
            memset((unsigned char *)buf, 0, size);
            break;
        } /* end if */

        size -= bytes_read;
        addr += (haddr_t)bytes_read;
        buf = (char *)buf + bytes_read;
    } /* end while */

    /* Update the file position data. */
    file->op  = H5FD_STDIO_OP_READ;
    file->pos = addr;

    return 0;
}

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_write
 *
 * Purpose:  Writes SIZE bytes from the beginning of BUF into file LF at
 *    file address ADDR.
 *
 * Errors:
 *    IO    SEEKERROR   fseek failed.
 *    IO    WRITEERROR  fwrite failed.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Robb Matzke
 *    Wednesday, October 22, 1997
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_write(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, hid_t /*UNUSED*/ dxpl_id, haddr_t addr,
                 size_t size, const void *buf)
{
    H5FD_stdio_t *     file = (H5FD_stdio_t *)_file;
    static const char *func = "H5FD_stdio_write"; /* Function Name for error reporting */

    /* Quiet the compiler */
    (void)dxpl_id;
    (void)type;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Check for overflow conditions */
    if (HADDR_UNDEF == addr)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1);
    if (REGION_OVERFLOW(addr, size))
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1);

    /* Seek to the correct file position. */
    if ((file->op != H5FD_STDIO_OP_WRITE && file->op != H5FD_STDIO_OP_SEEK) || file->pos != addr) {
        if (file_fseek(file->fp, (file_offset_t)addr, SEEK_SET) < 0) {
            file->op  = H5FD_STDIO_OP_UNKNOWN;
            file->pos = HADDR_UNDEF;
            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "fseek failed", -1);
        }
        file->pos = addr;
    }

    /* Write the buffer.  On successful return, the file position will be
     * advanced by the number of bytes read.  On failure, the file position is
     * undefined.
     */
    while (size > 0) {

        size_t bytes_in    = 0; /* # of bytes to write  */
        size_t bytes_wrote = 0; /* # of bytes written   */
        size_t item_size   = 1; /* size of items in bytes */

        if (size > H5_STDIO_MAX_IO_BYTES_g)
            bytes_in = H5_STDIO_MAX_IO_BYTES_g;
        else
            bytes_in = size;

        bytes_wrote = fwrite(buf, item_size, bytes_in, file->fp);

        if (bytes_wrote != bytes_in || (0 == bytes_wrote && ferror(file->fp))) { /* error */
            file->op  = H5FD_STDIO_OP_UNKNOWN;
            file->pos = HADDR_UNDEF;
            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "fwrite failed", -1);
        } /* end if */

        assert(bytes_wrote > 0);
        assert((size_t)bytes_wrote <= size);

        size -= bytes_wrote;
        addr += (haddr_t)bytes_wrote;
        buf = (const char *)buf + bytes_wrote;
    }

    /* Update seek optimizing data. */
    file->op  = H5FD_STDIO_OP_WRITE;
    file->pos = addr;

    /* Update EOF if necessary */
    if (file->pos > file->eof)
        file->eof = file->pos;

    return 0;
}

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_flush
 *
 * Purpose:  Makes sure that all data is on disk.
 *
 * Errors:
 *    IO    SEEKERROR     fseek failed.
 *    IO    WRITEERROR    fflush or fwrite failed.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Robb Matzke
 *    Wednesday, October 22, 1997
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_flush(H5FD_t *_file, hid_t /*UNUSED*/ dxpl_id, hbool_t closing)
{
    H5FD_stdio_t *     file = (H5FD_stdio_t *)_file;
    static const char *func = "H5FD_stdio_flush"; /* Function Name for error reporting */

    /* Quiet the compiler */
    (void)dxpl_id;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Only try to flush the file if we have write access */
    if (file->write_access) {
        if (!closing) {
            if (fflush(file->fp) < 0)
                H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "fflush failed", -1);

            /* Reset last file I/O information */
            file->pos = HADDR_UNDEF;
            file->op  = H5FD_STDIO_OP_UNKNOWN;
        } /* end if */
    }     /* end if */

    return 0;
} /* end H5FD_stdio_flush() */

/*-------------------------------------------------------------------------
 * Function:  H5FD_stdio_truncate
 *
 * Purpose:  Makes sure that the true file size is the same (or larger)
 *    than the end-of-address.
 *
 * Errors:
 *    IO    SEEKERROR     fseek failed.
 *    IO    WRITEERROR    fflush or fwrite failed.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Quincey Koziol
 *    Thursday, January 31, 2008
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_truncate(H5FD_t *_file, hid_t /*UNUSED*/ dxpl_id, hbool_t /*UNUSED*/ closing)
{
    H5FD_stdio_t *     file = (H5FD_stdio_t *)_file;
    static const char *func = "H5FD_stdio_truncate"; /* Function Name for error reporting */

    /* Quiet the compiler */
    (void)dxpl_id;
    (void)closing;

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    /* Only try to flush the file if we have write access */
    if (file->write_access) {
        /* Makes sure that the true file size is the same as the end-of-address. */
        if (file->eoa != file->eof) {

#ifdef H5_HAVE_WIN32_API
            LARGE_INTEGER li;       /* 64-bit (union) integer for SetFilePointer() call */
            DWORD         dwPtrLow; /* Low-order pointer bits from SetFilePointer()
                                     * Only used as an error code here.
                                     */
            DWORD dwError;          /* DWORD error code from GetLastError() */
            BOOL  bError;           /* Boolean error flag */

            /* Reset seek offset to beginning of file, so that file isn't re-extended later */
            rewind(file->fp);

            /* Windows uses this odd QuadPart union for 32/64-bit portability */
            li.QuadPart = (__int64)file->eoa;

            /* Extend the file to make sure it's large enough.
             *
             * Since INVALID_SET_FILE_POINTER can technically be a valid return value
             * from SetFilePointer(), we also need to check GetLastError().
             */
            dwPtrLow = SetFilePointer(file->hFile, li.LowPart, &li.HighPart, FILE_BEGIN);
            if (INVALID_SET_FILE_POINTER == dwPtrLow) {
                dwError = GetLastError();
                if (dwError != NO_ERROR)
                    H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_FILEOPEN, "unable to set file pointer", -1);
            }

            bError = SetEndOfFile(file->hFile);
            if (0 == bError)
                H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR,
                            "unable to truncate/extend file properly", -1);
#else  /* H5_HAVE_WIN32_API */
            /* Reset seek offset to beginning of file, so that file isn't re-extended later */
            rewind(file->fp);

            /* Truncate file to proper length */
            if (-1 == file_ftruncate(file->fd, (file_offset_t)file->eoa))
                H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR,
                            "unable to truncate/extend file properly", -1);
#endif /* H5_HAVE_WIN32_API */

            /* Update the eof value */
            file->eof = file->eoa;

            /* Reset last file I/O information */
            file->pos = HADDR_UNDEF;
            file->op  = H5FD_STDIO_OP_UNKNOWN;
        } /* end if */
    }     /* end if */
    else {
        /* Double-check for problems */
        if (file->eoa > file->eof)
            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_TRUNCATED, "eoa > eof!", -1);
    } /* end else */

    return 0;
} /* end H5FD_stdio_truncate() */

/*-------------------------------------------------------------------------
 * Function:    H5FD_stdio_lock
 *
 * Purpose:     Lock a file via flock
 *              NOTE: This function is a no-op if flock() is not present.
 *
 * Errors:
 *    IO    FCNTL    flock failed.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Vailin Choi; March 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_lock(H5FD_t *_file, hbool_t rw)
{
#ifdef H5_HAVE_FLOCK
    H5FD_stdio_t *     file = (H5FD_stdio_t *)_file; /* VFD file struct                      */
    int                lock_flags;                   /* file locking flags                   */
    static const char *func = "H5FD_stdio_lock";     /* Function Name for error reporting    */

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    assert(file);

    /* Set exclusive or shared lock based on rw status */
    lock_flags = rw ? LOCK_EX : LOCK_SH;

    /* Place a non-blocking lock on the file */
    if (flock(file->fd, lock_flags | LOCK_NB) < 0) {
        if (file->ignore_disabled_file_locks && ENOSYS == errno)
            /* When errno is set to ENOSYS, the file system does not support
             * locking, so ignore it.
             */
            errno = 0;
        else
            H5Epush_ret(func, H5E_ERR_CLS, H5E_VFL, H5E_CANTLOCKFILE, "file lock failed", -1);
    } /* end if */

    /* Flush the stream */
    if (fflush(file->fp) < 0)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "fflush failed", -1);

#endif /* H5_HAVE_FLOCK */

    return 0;
} /* end H5FD_stdio_lock() */

/*-------------------------------------------------------------------------
 * Function:    H5F_stdio_unlock
 *
 * Purpose:     Unlock a file via flock
 *              NOTE: This function is a no-op if flock() is not present.
 *
 * Errors:
 *    IO    FCNTL    flock failed.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Vailin Choi; March 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_unlock(H5FD_t *_file)
{
#ifdef H5_HAVE_FLOCK
    H5FD_stdio_t *     file = (H5FD_stdio_t *)_file; /* VFD file struct                      */
    static const char *func = "H5FD_stdio_unlock";   /* Function Name for error reporting    */

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    assert(file);

    /* Flush the stream */
    if (fflush(file->fp) < 0)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "fflush failed", -1);

    /* Place a non-blocking lock on the file */
    if (flock(file->fd, LOCK_UN) < 0) {
        if (file->ignore_disabled_file_locks && ENOSYS == errno)
            /* When errno is set to ENOSYS, the file system does not support
             * locking, so ignore it.
             */
            errno = 0;
        else
            H5Epush_ret(func, H5E_ERR_CLS, H5E_VFL, H5E_CANTUNLOCKFILE, "file unlock failed", -1);
    } /* end if */

#endif /* H5_HAVE_FLOCK */

    return 0;
} /* end H5FD_stdio_unlock() */

/*-------------------------------------------------------------------------
 * Function:    H5FD_stdio_delete
 *
 * Purpose:     Delete a file
 *
 * Return:      Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_stdio_delete(const char *filename, hid_t /*UNUSED*/ fapl_id)
{
    static const char *func = "H5FD_stdio_delete"; /* Function Name for error reporting    */

    /* Clear the error stack */
    H5Eclear2(H5E_DEFAULT);

    assert(filename);

    /* Quiet compiler */
    (void)fapl_id;

    if (remove(filename) < 0)
        H5Epush_ret(func, H5E_ERR_CLS, H5E_VFL, H5E_CANTDELETEFILE, "can't delete file)", -1);

    return 0;
} /* end H5FD_stdio_delete() */

#ifdef H5private_H
/*
 * This is not related to the functionality of the driver code.
 * It is added here to trigger warning if HDF5 private definitions are included
 * by mistake.  The code should use only HDF5 public API and definitions.
 */
#error "Do not use HDF5 private definitions"
#endif