summaryrefslogtreecommitdiffstats
path: root/doc/html/RM_H5D.html
blob: 63753c30ed800f643cd77723e4e4c6c821fdce7c (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
<html>
<head><title>
HDF5/H5D API Specification
</title></head>

<body bgcolor="#FFFFFF">


<hr>
<center>
<table border=0 width=98%>
<tr><td valign=top align=left>
<a href="H5.intro.html">Introduction to HDF5</a>&nbsp;<br>
<a href="H5.user.html">HDF5 User Guide</a>&nbsp;<br>
<a href="index.html">Other HDF5 documents and links</a>&nbsp;<br>
<!--
<a href="Glossary.html">Glossary</a><br>
-->
</td>
<td valign=top align=right>
And in this document, the 
<a href="RM_H5Front.html">HDF5 Reference Manual</a>&nbsp;&nbsp;
<br>
<a href="RM_H5.html">H5</a>&nbsp;&nbsp;
<a href="RM_H5A.html">H5A</a>&nbsp;&nbsp;
H5D&nbsp;&nbsp;
<a href="RM_H5E.html">H5E</a>&nbsp;&nbsp;
<a href="RM_H5F.html">H5F</a>&nbsp;&nbsp;
<a href="RM_H5G.html">H5G</a>&nbsp;&nbsp;
<a href="RM_H5I.html">H5I</a>&nbsp;&nbsp;
<br>
<a href="RM_H5P.html">H5P</a>&nbsp;&nbsp;
<a href="RM_H5R.html">H5R</a>&nbsp;&nbsp;
<a href="RM_H5RA.html">H5RA</a>&nbsp;&nbsp;
<a href="RM_H5S.html">H5S</a>&nbsp;&nbsp;
<a href="RM_H5T.html">H5T</a>&nbsp;&nbsp;
<a href="RM_H5Z.html">H5Z</a>&nbsp;&nbsp;
<a href="Tools.html">Tools</a>&nbsp;&nbsp;
</td></tr>
</table>
</center>
<hr>


<center>
<h1>H5D: Datasets Interface</h1>
</center>

<h2>Dataset Object API Functions</h2>

These functions create and manipulate dataset objects, 
and set and retrieve their constant or persistent properties.

<p>
<strong>The C Interfaces:</strong>

<table border=0>
<tr><td valign=top>
<ul>
    <li><a href="#Dataset-Create">H5Dcreate</a>
    <li><a href="#Dataset-Open">H5Dopen</a>
    <li><a href="#Dataset-Close">H5Dclose</a>
    <li><a href="#Dataset-GetSpace">H5Dget_space</a>
    <li><a href="#Dataset-GetType">H5Dget_type</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
    <li><a href="#Dataset-GetCreatePlist">H5Dget_create_plist</a>
    <li><a href="#Dataset-GetStorageSize">H5Dget_storage_size</a>
    <li><a href="#Dataset-GetVLBuf">H5Dget_vlen_buf_size</a>
    <li><a href="#Dataset-VLReclaim">H5Dvlen_reclaim</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
    <li><a href="#Dataset-Read">H5Dread</a>
    <li><a href="#Dataset-Write">H5Dwrite</a>
    <li><a href="#Dataset-Iterate">H5Diterate</a>
<!--
    <li><a href="#Dataset-Debug">H5Ddebug</a>
-->
    <li><a href="#Dataset-Extend">H5Dextend</a>
</ul>
</td></tr>
</table>

<p>
<strong>The FORTRAN90 Interfaces:</strong>

<br>
<font size=-1>
<i>In general, each FORTRAN90 subroutine performs exactly the same task 
as the corresponding C function.  The links below go to the C function 
descriptions, which serve as general descriptions for both.  A button, 
under <strong>Non-C API(s)</strong> at the end of the C function description,
opens an external browser window displaying the FORTRAN90-specific 
information.  You will probably want to adjust the size and location of 
this external window so that both browser windows are visible and to 
facilitate moving easily between them.</i>
</font>

<table border=0>
<tr><td valign=top>
<ul>
    <li><a href="#Dataset-Create">h5dcreate_f</a>
    <li><a href="#Dataset-Open">h5dopen_f</a>
    <li><a href="#Dataset-Close">h5dclose_f</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
    <li><a href="#Dataset-GetSpace">h5dget_space_f</a>
    <li><a href="#Dataset-GetType">h5dget_type_f</a>
    <li><a href="#Dataset-GetCreatePlist">h5dget_create_plist_f</a>
<!--<li><a href="#Dataset-GetStorageSize">h5dget_storage_size_f</a>      -->
<!--<li><a href="#Dataset-GetVLBuf">h5dget_vlen_buf_size_f</a>           -->
<!--<li><a href="#Dataset-VLReclaim">h5dvlen_reclaim_f</a>               -->
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
    <li><a href="#Dataset-Read">h5dread_f</a>
    <li><a href="#Dataset-Write">h5dwrite_f</a>
<!--<li><a href="#Dataset-Iterate">h5diterate_f</a>                     -->
<!--<li><a href="#Dataset-Debug">h5ddebug_f</a>                         -->
    <li><a href="#Dataset-Extend">h5dextend_f</a>
</ul>
</td></tr>
</table>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Create">H5Dcreate</a>
<dt><strong>Signature:</strong>
    <dd><em>hid_t </em><code>H5Dcreate</code>(<em>hid_t </em><code>loc_id</code>,
        <em>const char *</em><code>name</code>,
        <em>hid_t</em><code>type_id</code>,
        <em>hid_t</em><code>space_id</code>,
        <em>hid_t</em><code>create_plist_id</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Creates a dataset at the specified location.
<dt><strong>Description:</strong>
    <dd><code>H5Dcreate</code> creates a data set with a name, 
        <code>name</code>, in the file or in the group specified by 
        the identifier <code>loc_id</code>.
        The dataset has the datatype and dataspace identified by
        <code>type_id</code> and <code>space_id</code>, respectively.
        The specified datatype and dataspace are the datatype and
        dataspace of the dataset as it will exist in the file,
        which may be different than in application memory.
        Dataset creation properties are specified by the argument
        <code>create_plist_id</code>.
        <p>
        <code>create_plist_id</code> is a <code>H5P_DATASET_CREATE</code>
        property list created with <code>H5Pcreate()</code> and
        initialized with the various functions described above.
        <code>H5Dcreate()</code> returns a dataset identifier for success
        or negative for failure. The identifier should eventually be
        closed by calling <code>H5Dclose()</code> to release resources
        it uses.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>loc_id</code>
            <dd>Identifier of the file or group to create the dataset within.
        <dt><em>const char *</em> <code>name</code>
            <dd>The name of the dataset to create.
        <dt><em>hid_t</em> <code>type_id</code>
            <dd>Identifier of the datatype to use when creating the dataset.
        <dt><em>hid_t</em> <code>space_id</code>
            <dd>Identifier of the dataspace to use when creating the dataset.
        <dt><em>hid_t</em> <code>create_plist_id</code>
            <dd>Identifier of the set creation property list.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a dataset identifier if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dcreate_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Open">H5Dopen</a>
<dt><strong>Signature:</strong>
    <dd><em>hid_t </em><code>H5Dopen</code>(<em>hid_t </em><code>loc_id</code>,
        <em>const char *</em><code>name</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Opens an existing dataset.
<dt><strong>Description:</strong>
    <dd><code>H5Dopen</code> opens an existing dataset for access in the file
        or group specified in <code>loc_id</code>.  <code>name</code> is
        a dataset name and is used to identify the dataset in the file.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>loc_id</code>
            <dd>Identifier of the dataset to open or the file or group
                to access the dataset within.
        <dt><em>const char *</em> <code>name</code>
            <dd>The name of the dataset to access.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a dataset identifier if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dopen_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-GetSpace">H5Dget_space</a>
<dt><strong>Signature:</strong>
    <dd><em>hid_t </em><code>H5Dget_space</code>(<em>hid_t </em><code>dataset_id</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Returns an identifier for  a copy of the dataspace for a dataset.
<dt><strong>Description:</strong>
    <dd><code>H5Dget_space</code> returns an identifier for a copy of the 
        dataspace for a dataset.  
        The dataspace identifier should be released with the 
        <code>H5Sclose()</code> function.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset to query.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a dataspace identifier if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dget_space_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-GetType">H5Dget_type</a>
<dt><strong>Signature:</strong>
    <dd><em>hid_t </em><code>H5Dget_type</code>(<em>hid_t </em><code>dataset_id</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Returns an identifier for a copy of the datatype for a dataset.
<dt><strong>Description:</strong>
    <dd><code>H5Dget_type</code> returns an identifier for a copy of the 
        datatype for a dataset.  
        The datatype should be released with the <code>H5Tclose()</code> function.
        <p>
        If a dataset has a named datatype, then an identifier to the 
        opened datatype is returned.  
        Otherwise, the returned datatype is read-only.  
        If atomization of the datatype fails, then the datatype is closed.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset to query.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a datatype identifier if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dget_type_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-GetCreatePlist">H5Dget_create_plist</a>
<dt><strong>Signature:</strong>
    <dd><em>hid_t </em><code>H5Dget_create_plist</code>(<em>hid_t </em><code>dataset_id</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Returns an identifier for a copy of the 
        dataset creation property list for a dataset.
<dt><strong>Description:</strong>
    <dd><code>H5Dget_create_plist</code> returns an identifier for a 
        copy of the dataset creation property list for a dataset.
        The creation property list identifier should be released with 
        the <code>H5Pclose()</code> function.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset to query.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a dataset creation property list identifier if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dget_create_plist_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-GetStorageSize">H5Dget_storage_size</a>
<dt><strong>Signature:</strong>
    <dd><em>hsize_t </em><code>H5Dget_storage_size</code>(<em>hid_t </em><code>dataset_id</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Returns the amount of storage required for a dataset.
<dt><strong>Description:</strong>
    <dd><code>H5Dget_storage_size</code> returns the amount of storage 
        that is required for the specified dataset, <code>dataset_id</code>. 
        For chunked datasets, this is the number of allocated chunks times 
        the chunk size.        
        The return value may be zero if no data has been stored.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset to query.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns the amount of storage space allocated for the dataset, 
        not counting meta data; 
        otherwise returns a negative value.
<!--
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dget_storage_size" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
-->     <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-GetVLBuf">H5Dget_vlen_buf_size</a>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<i><b>(Not yet implemented.)</b></i>
<dt><strong>Signature:</strong>   
    <dd><em>herr_t </em><code>H5Dget_vlen_buf_size</code>(<em>hid_t </em><code>dataset_id</code>,
    <em>hid_t</em> <code>type_id</code>,
    <em>hid_t</em> <code>space_id</code>,
    <em>hsize_t</em> *<code>size</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Determines the number of bytes required to store VL data.
<dt><strong>Description:</strong>
    <dd><code>H5Dget_vlen_buf_size</code> determines the number of bytes 
        required to store the VL data from the dataset, using the 
        <code>space_id</code> for the selection in the dataset on 
        disk and the <code>type_id</code> for the memory representation 
        of the VL data in memory.  
        <p>
        <code>*size</code> is returned with the number of bytes are 
        required to store the VL data in memory.          
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset to query.
        <dt><em>hid_t</em> <code>type_id</code>
            <dd>Identifier of the datatype.
        <dt><em>hid_t</em> <code>space_id</code>
            <dd>Identifier of the dataspace.
        <dt><em>hsize_t</em> *<code>size</code>
            <dd>The size in bytes of the buffer required to store the VL data.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns non-negative value if successful;
        otherwise returns a negative value.
<!--
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dget_vlen_buf_size_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
-->     <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-VLReclaim">H5Dvlen_reclaim</a>
<dt><strong>Signature:</strong>
    <dd><em>herr_t </em><code>H5Dvlen_reclaim</code>(<em>hid_t </em><code>type_id</code>
    <em>hid_t</em> <code>space_id</code>,
    <em>hid_t</em> <code>plist_id</code>,
    <em>void</em> *<code>buf</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Reclaims VL datatype memory buffers.
<dt><strong>Description:</strong>
    <dd><code>H5Dvlen_reclaim</code> reclaims memory buffers created to 
        store VL datatypes.
        <p>
        The <code>type_id</code> must be the datatype stored in the buffer.
        The <code>space_id</code> describes the selection for the memory buffer 
        to free the VL datatypes within.  
        The <code>plist_id</code> is the dataset transfer property list which 
        was used for the I/O transfer to create the buffer.
        And <code>buf</code> is the pointer to the buffer to be reclaimed.
        <p>
        The VL structures (<code>hvl_t</code>) in the user's buffer are 
        modified to zero out the VL information after the memory has been reclaimed.
        <p>
        If nested VL datatypes were used to create the buffer, 
        this routine frees them <em>from the bottom up</em>, releasing all 
        the memory without creating memory leaks.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>type_id</code>
            <dd>Identifier of the datatype.
        <dt><em>hid_t</em> <code>space_id</code>
            <dd>Identifier of the dataspace.
        <dt><em>hid_t</em> <code>plist_id</code>
            <dd>Identifier of the property list used to create the buffer.
        <dt><em>void</em> *<code>buf</code>
            <dd>Pointer to the buffer to be reclaimed.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns non-negative value if successful;
        otherwise returns a negative value.
<!--
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dvlen_reclaim_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
-->     <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Read">H5Dread</a>
<dt><strong>Signature:</strong>
    <dd><em>herr_t </em><code>H5Dread</code>(<em>hid_t </em><code>dataset_id</code>,
        <em>hid_t</em> <code>mem_type_id</code>,
        <em>hid_t</em> <code>mem_space_id</code>,
        <em>hid_t</em> <code>file_space_id</code>,
        <em>hid_t</em> <code>xfer_plist_id</code>,
        <em>void *</em> <code>buf</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Reads raw data from the specified dataset into <code>buf</code>,
        converting from file datatype and dataspace to 
        memory datatype and dataspace.
<dt><strong>Description:</strong>
    <dd><code>H5Dread</code> reads a (partial) dataset, specified by its
        identifier <code>dataset_id</code>, from the file into the 
        application memory buffer <code>buf</code>.
        Data transfer properties are defined by the argument 
        <code>xfer_plist_id</code>.
        The memory datatype of the (partial) dataset is identified by 
        the identifier <code>mem_type_id</code>.
        The part of the dataset to read is defined by 
        <code>mem_space_id</code> and <code>file_space_id</code>.
        <p>
        <code>file_space_id</code> can be the constant <code>H5S_ALL</code>, 
        which indicates that the entire file data space is to be referenced.
        <p>
        <code>mem_space_id</code> can be the constant <code>H5S_ALL</code>, 
        in which case the memory data space is the same as the file data space
        defined when the dataset was created.
        <p>
        The number of elements in the memory data space must match
        the number of elements in the file data space.
        <p>
        <code>xfer_plist_id</code> can be the constant <code>H5P_DEFAULT</code>, 
        in which case the default data transfer properties are used.
 
        <p>
        Datatype conversion takes place at the time of a read or write
        and is automatic.  See the
        <a href="Datatypes.html#Datatypes-DataConversion">Data Conversion</a> 
        section of <cite>The Data Type Interface (H5T)</cite> in the 
        <cite>HDF5 User's Guide</cite> for a discussion of 
        data conversion, including the range of conversions currently 
        supported by the HDF5 libraries.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset read from.
        <dt><em>hid_t</em> <code>mem_type_id</code>
            <dd>Identifier of the memory datatype.
        <dt><em>hid_t</em> <code>mem_space_id</code>
            <dd>Identifier of the memory dataspace.
        <dt><em>hid_t</em> <code>file_space_id</code>
            <dd>Identifier of the dataset's dataspace in the file.
        <dt><em>hid_t</em> <code>xfer_plist_id</code>
            <dd>Identifier of a transfer property list for this I/O operation.
        <dt><em>void *</em> <code>buf</code>
            <dd>Buffer to store data read from the file.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a non-negative value if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dread_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Write">H5Dwrite</a>
<dt><strong>Signature:</strong>
    <dd><em>herr_t </em><code>H5Dwrite</code>(<em>hid_t </em><code>dataset_id</code>,
        <em>hid_t</em> <code>mem_type_id</code>,
        <em>hid_t</em> <code>mem_space_id</code>,
        <em>hid_t</em> <code>file_space_id</code>,
        <em>hid_t</em> <code>xfer_plist_id</code>,
        <em>const void *</em> <code>buf</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Writes raw data from an application buffer <code>buf</code> to 
        the specified dataset, converting from 
        memory datatype and dataspace to file datatype and dataspace.
<dt><strong>Description:</strong>
    <dd><code>H5Dwrite</code> writes a (partial) dataset, specified by its
        identifier <code>dataset_id</code>, from the 
        application memory buffer <code>buf</code> into the file.
        Data transfer properties are defined by the argument 
        <code>xfer_plist_id</code>.
        The memory datatype of the (partial) dataset is identified by 
        the identifier <code>mem_type_id</code>.
        The part of the dataset to write is defined by 
        <code>mem_space_id</code> and <code>file_space_id</code>.
        <p>
        <code>file_space_id</code> can be the constant <code>H5S_ALL</code>. 
        which indicates that the entire file data space is to be referenced.
        <p>
        <code>mem_space_id</code> can be the constant <code>H5S_ALL</code>,
        in which case the memory data space is the same as the file data space
        defined when the dataset was created.
        <p>
        The number of elements in the memory data space must match
        the number of elements in the file data space.
        <p>
        <code>xfer_plist_id</code> can be the constant <code>H5P_DEFAULT</code>.
        in which case the default data transfer properties are used.           
        <p>
        Writing to an external dataset will fail if the HDF5 file is 
        not open for writing.
        <p>
        Datatype conversion takes place at the time of a read or write
        and is automatic.  See the
        <a href="Datatypes.html#Datatypes-DataConversion">Data Conversion</a> 
        section of <cite>The Data Type Interface (H5T)</cite> in the 
        <cite>HDF5 User's Guide</cite> for a discussion of 
        data conversion, including the range of conversions currently 
        supported by the HDF5 libraries.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset read from.
        <dt><em>hid_t</em> <code>mem_type_id</code>
            <dd>Identifier of the memory datatype.
        <dt><em>hid_t</em> <code>mem_space_id</code>
            <dd>Identifier of the memory dataspace.
        <dt><em>hid_t</em> <code>file_space_id</code>
            <dd>Identifier of the dataset's dataspace in the file.
        <dt><em>hid_t</em> <code>xfer_plist_id</code>
            <dd>Identifier of a transfer property list for this I/O operation.
        <dt><em>const void *</em> <code>buf</code>
            <dd>Buffer with data to be written to the file.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a non-negative value if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dwrite_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Extend">H5Dextend</a>
<dt><strong>Signature:</strong>
    <dd><em>herr_t </em><code>H5Dextend</code>(<em>hid_t </em><code>dataset_id</code>,
        <em>const hsize_t *</em> <code>size</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Extends a dataset with unlimited dimension.
<dt><strong>Description:</strong>
    <dd><code>H5Dextend</code> verifies that the dataset is at least of size
        <code>size</code>.  
        The dimensionality of <code>size</code> is the same as that of
        the dataspace of the dataset being changed.
        This function cannot be applied to a dataset with fixed dimensions.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset.
        <dt><em>const hsize_t *</em> <code>size</code>
            <dd>Array containing the new magnitude of each dimension.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a non-negative value if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dextend_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Close">H5Dclose</a>
<dt><strong>Signature:</strong>
    <dd><em>hid_t </em><code>H5Dclose</code>(<em>hid_t </em><code>dataset_id</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Closes the specified dataset.
<dt><strong>Description:</strong>
    <dd><code>H5Dclose</code> ends access to a dataset specified by 
        <code>dataset_id</code> and releases resources used by it.
        Further use of the dataset identifier is illegal in calls to 
        the dataset API.
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>hid_t</em> <code>dataset_id</code>
            <dd>Identifier of the dataset to finish access to.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns a non-negative value if successful;
        otherwise returns a negative value.
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5dclose_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
        <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>


<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Iterate">H5Diterate</a>
<dt><strong>Signature:</strong>
    <dd><em>herr_t </em><code>H5Diterate</code>(
        <em>void *</em><code>buf</code>,
        <em>hid_t </em><code>type_id</code>,
        <em>hid_t </em><code>space_id</code>,
        <em>H5D_operator_t </em><code>operator</code>,
        <em>void *</em><code>operator_data</code>
    )
<dt><strong>Purpose:</strong>
    <dd>Iterates over all selected elements in a dataspace.
<dt><strong>Description:</strong>
    <dd><code>H5Diterate</code> iterates over all the elements selected 
        in a memory buffer.  The callback function is called once for each 
        element selected in the dataspace.  
        <p>
        The selection in the dataspace is modified so that any elements 
        already iterated over are removed from the selection if the 
        iteration is interrupted (by the <code>H5D_operator_t</code> 
        function returning non-zero) before the iteration is complete;
        the iteration may then be re-started by the user where it left off.  
        
<dt><strong>Parameters:</strong>
    <dl>
        <dt><em>void *</em><code>buf</code>
            <dd>IN/OUT: Pointer to the buffer in memory containing the 
                elements to iterate over.
        <dt><em>hid_t </em><code>type_id</code>
            <dd>IN:  Datatype identifier for the elements stored in 
                <code>buf</code>.
        <dt><em>hid_t </em><code>space_id</code>
            <dd>IN: Dataspace identifier for <code>buf</code>.  
                Also contains the selection to iterate over.
        <dt><em>H5D_operator_t </em><code>operator</code>
            <dd>IN: Function pointer to the routine to be called 
                for each element in <code>buf</code> iterated over.
        <dt><em>void *</em><code>operator_data</code>
            <dd>IN/OUT: Pointer to any user-defined data associated 
                with the operation.
    </dl>
<dt><strong>Returns:</strong>
    <dd>Returns the return value of the last operator if it was non-zero,
        or zero if all elements have been processed.
        Otherwise returns a negative value.
<!--
<dt><strong>Non-C API(s):</strong>
    <dd><a href="fortran/h5d_FORTRAN.html#h5diterate_f" 
        target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
-->     <!--
        <img src="Graphics/Java.gif"> 
        <img src="Graphics/C++.gif">
        -->
</dl>



<hr>
<center>
<table border=0 width=98%>
<tr><td valign=top align=left>
<a href="H5.intro.html">Introduction to HDF5</a>&nbsp;<br>
<a href="H5.user.html">HDF5 User Guide</a>&nbsp;<br>
<a href="index.html">Other HDF5 documents and links</a>&nbsp;<br>
<!--
<a href="Glossary.html">Glossary</a><br>
-->
</td>
<td valign=top align=right>
And in this document, the 
<a href="RM_H5Front.html">HDF5 Reference Manual</a>&nbsp;&nbsp;
<br>
<a href="RM_H5.html">H5</a>&nbsp;&nbsp;
<a href="RM_H5A.html">H5A</a>&nbsp;&nbsp;
H5D&nbsp;&nbsp;
<a href="RM_H5E.html">H5E</a>&nbsp;&nbsp;
<a href="RM_H5F.html">H5F</a>&nbsp;&nbsp;
<a href="RM_H5G.html">H5G</a>&nbsp;&nbsp;
<a href="RM_H5I.html">H5I</a>&nbsp;&nbsp;
<br>
<a href="RM_H5P.html">H5P</a>&nbsp;&nbsp;
<a href="RM_H5R.html">H5R</a>&nbsp;&nbsp;
<a href="RM_H5RA.html">H5RA</a>&nbsp;&nbsp;
<a href="RM_H5S.html">H5S</a>&nbsp;&nbsp;
<a href="RM_H5T.html">H5T</a>&nbsp;&nbsp;
<a href="RM_H5Z.html">H5Z</a>&nbsp;&nbsp;
<a href="Tools.html">Tools</a>&nbsp;&nbsp;
</td></tr>
</table>
</center>
<hr>


<address>
<a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a> 

<br>
Last modified:  20 October 1999

</body>
</html>