hdf5/doc/html/RM_H5D.html
Quincey Koziol 427ff7da28 [svn-r9727] Purpose:
Bug Fix/Code Cleanup/Doc Cleanup/Optimization/Branch Sync :-)

Description:
    Generally speaking, this is the "signed->unsigned" change to selections.
However, in the process of merging code back, things got stickier and stickier
until I ended up doing a big "sync the two branches up" operation.  So... I
brought back all the "infrastructure" fixes from the development branch to the
release branch (which I think were actually making some improvement in
performance) as well as fixed several bugs which had been fixed in one branch,
but not the other.

    I've also tagged the repository before making this checkin with the label
"before_signed_unsigned_changes".

Platforms tested:
    FreeBSD 4.10 (sleipnir) w/parallel & fphdf5
    FreeBSD 4.10 (sleipnir) w/threadsafe
    FreeBSD 4.10 (sleipnir) w/backward compatibility
    Solaris 2.7 (arabica) w/"purify options"
    Solaris 2.8 (sol) w/FORTRAN & C++
    AIX 5.x (copper) w/parallel & FORTRAN
    IRIX64 6.5 (modi4) w/FORTRAN
    Linux 2.4 (heping) w/FORTRAN & C++


Misc. update:
2004-12-29 09:26:20 -05:00

1575 lines
62 KiB
HTML

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<head><title>
HDF5/H5D API Specification
</title>
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<center>
<table border=0 width=98%>
<tr><td valign=top align=left>
<a href="index.html">HDF5 documents and links</a>&nbsp;<br>
<a href="H5.intro.html">Introduction to HDF5</a>&nbsp;<br>
<a href="http://hdf.ncsa.uiuc.edu/HDF5/doc/UG/index.html">HDF5 User Guide</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;
<a href="RM_H5D.html">H5D</a>&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;
<a href="RM_H5P.html">H5P</a>&nbsp;&nbsp;
<br>
<a href="RM_H5R.html">H5R</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;
<a href="PredefDTypes.html">Datatypes</a>&nbsp;&nbsp;
</td></tr>
</table>
</center>
<hr><!-- #EndLibraryItem --><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-GetSpaceStatus">H5Dget_space_status</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
<li><a href="#Dataset-GetType">H5Dget_type</a>
<li><a href="#Dataset-GetCreatePlist">H5Dget_create_plist</a>
<li><a href="#Dataset-GetOffset">H5Dget_offset</a>
<li><a href="#Dataset-GetStorageSize">H5Dget_storage_size</a>
<li><a href="#Dataset-VLGetBuf">H5Dvlen_get_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-Debug">H5Ddebug</a>
This function is in the distributed source code and is technically
a public function, but it is NOT intended for public use.
It is used only by certain tools.
DO NOT list it in the Reference Manual.
-->
<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-Extend">H5Dextend</a>
<li><a href="#Dataset-Fill">H5Dfill</a>
</ul>
</td></tr>
</table>
<br>
<i>Alphabetical Listing</i>
<table border="0">
<tr>
<td valign="top">
<ul>
<li><a href="#Dataset-Close">H5Dclose</a>
<li><a href="#Dataset-Create">H5Dcreate</a>
<li><a href="#Dataset-Extend">H5Dextend</a>
<li><a href="#Dataset-Fill">H5Dfill</a>
<li><a href="#Dataset-GetCreatePlist">H5Dget_create_plist</a>
<li><a href="#Dataset-GetOffset">H5Dget_offset</a>
</ul>
</td>
<td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td valign="top">
<ul>
<li><a href="#Dataset-GetSpace">H5Dget_space</a>
<li><a href="#Dataset-GetSpaceStatus">H5Dget_space_status</a>
<li><a href="#Dataset-GetStorageSize">H5Dget_storage_size</a>
<li><a href="#Dataset-GetType">H5Dget_type</a>
<li><a href="#Dataset-Iterate">H5Diterate</a>
<li><a href="#Dataset-Open">H5Dopen</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-VLGetBuf">H5Dvlen_get_buf_size</a>
<li><a href="#Dataset-VLReclaim">H5Dvlen_reclaim</a>
<li><a href="#Dataset-Write">H5Dwrite</a>
</ul>
</td>
</tr>
</table>
<br>
<strong>The FORTRAN90 Interfaces:</strong>
<br>
In general, each FORTRAN90 subroutine performs exactly the same task
as the corresponding C function.
<br>
<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>
<li><a href="#Dataset-GetSpace">h5dget_space_f</a>
<li><a href="#Dataset-GetSpaceStatus">h5dget_space_status_f</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
<li><a href="#Dataset-GetType">h5dget_type_f</a>
<li><a href="#Dataset-GetCreatePlist">h5dget_create_plist_f</a>
<li><a href="#Dataset-GetOffset">h5dget_offset_f</a>
<li><a href="#Dataset-GetStorageSize">h5dget_storage_size_f</a>
<li><a href="#Dataset-VLGetBuf">h5dvlen_get_max_len_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>
<li><a href="#Dataset-Fill">h5dfill_f</a>
</ul>
</td></tr>
</table>
<!-- NEW PAGE -->
<!-- HEADER RIGHT " " -->
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Dclose" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Close">H5Dclose</a>
<dt><strong>Signature:</strong>
<dd><em>herr_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>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>dataset_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataset to close access to.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dclose_f
<dd>
<pre>
SUBROUTINE h5dclose_f(dset_id, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dset_id ! Dataset identifier
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dclose_f
</pre>
<!--<dt><strong>Non-C API(s):</strong>
<dd>
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Dcreate" -->
<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>
Dataset names within a group are unique:
<code>H5Dcreate</code> will return an error if a dataset with
the name specified in <code>name</code> already exists at the
location specified in <code>loc_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.
<p>
<code>H5Dcreate</code> returns an error if the dataset's datatype
includes a variable-length (VL) datatype and the fill value
is undefined, i.e., set to <code>NULL</code> in the
dataset creation property list.
Such a VL datatype may be directly included,
indirectly included as part of a compound or array datatype, or
indirectly included as part of a nested compound or array datatype.
<p>
<code>H5Dcreate</code> returns a dataset identifier for success
or a negative value for failure.
The dataset identifier should eventually be closed by
calling <code>H5Dclose</code> to release resources it uses.
<p>
<strong>Fill values and space allocation:</strong><br>
The HDF5 library provides flexible means
of specifying a fill value,
of specifying when space will be allocated for a dataset, and
of specifying when fill values will be written to a dataset.
For further information on these topics, see the document
<a href="http://hdf.ncsa.uiuc.edu/RFC/Fill_Value/FillValue.html">
<cite>Fill Value and Dataset Storage Allocation Issues in HDF5</cite></a>
and the descriptions of the following HDF5 functions in this
<cite>HDF5 Reference Manual</cite>:
<table width=80% border="0">
<tr valign="top" align="left"><td width=10%>&nbsp;
</td><td width=45%>
<a href="#Dataset-Fill"><code>H5Dfill</code></a><br>
<a href="RM_H5P.html#Property-SetFillValue"><code>H5Pset_fill_value</code></a><br>
<a href="RM_H5P.html#Property-GetFillValue"><code>H5Pget_fill_value</code></a><br>
<a href="RM_H5P.html#Property-FillValueDefined"><code>H5Pfill_value_defined</code></a>
</td><td width=45%>
<a href="RM_H5P.html#Property-SetFillTime"><code>H5Pset_fill_time</code></a><br>
<a href="RM_H5P.html#Property-GetFillTime"><code>H5Pget_fill_time</code></a><br>
<a href="RM_H5P.html#Property-SetAllocTime"><code>H5Pset_alloc_time</code></a><br>
<a href="RM_H5P.html#Property-GetAllocTime"><code>H5Pget_alloc_time</code></a>
</td></tr>
</table>
This information is also included in the
&ldquo;HDF5 Datasets&rdquo; chapter of
the new <cite>HDF5 User's Guide</cite>,
which is being prepared for release.
<dt><strong>Note:</strong>
<dd><code>H5Dcreate</code> can fail if there has been an error
in setting up an element of the dataset creation property list.
In such cases, each item in the property list must be examined
to ensure that the setup satisfies to all required conditions.
This problem is most likely to occur with the use of filters.
<p>
For example, <code>H5Dcreate</code> will fail without a meaningful
explanation if
<ul>
<li>SZIP compression is being used on the dataset and
<li>the SZIP parameter <code>pixels_per_block</code>
is set to an inappropriate value.
</ul>
<p>
In such a case, one would refer to the description of
<a href="RM_H5P.html#Property-SetSzip"><code>H5Pset_szip</code></a>,
looking for any conditions or requirements that might affect the
local computing environment.
<!--
<p>
Other known similar problems can occur with . . .
-->
<dt><strong>Parameters:</strong>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em> <code>loc_id</code></td>
<td valign="top">IN: Identifier of the file or group
within which to create the dataset.</td></tr>
<tr>
<td valign="top"><em>const char *</em> <code>name</code></td>
<td valign="top">IN: The name of the dataset to create.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>type_id</code></td>
<td valign="top">IN: Identifier of the datatype to use
when creating the dataset.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>space_id</code></td>
<td valign="top">IN: Identifier of the dataspace to use
when creating the dataset.</td></tr>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>create_plist_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the set creation property list.</td></tr>
</table></ul>
<!-- NEW PAGE -->
<dt><strong>Returns:</strong>
<dd>Returns a dataset identifier if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dcreate_f
<dd>
<pre>
SUBROUTINE h5dcreate_f(loc_id, name, type_id, space_id, dset_id, &
hdferr, creation_prp)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: loc_id ! File or group identifier
CHARACTER(LEN=*), INTENT(IN) :: name ! Name of the dataset
INTEGER(HID_T), INTENT(IN) :: type_id ! Datatype identifier
INTEGER(HID_T), INTENT(IN) :: space_id ! Dataspace identifier
INTEGER(HID_T), INTENT(OUT) :: dset_id ! Dataset identifier
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
INTEGER(HID_T), OPTIONAL, INTENT(IN) :: creation_prp
! Dataset creation propertly
! list identifier , default
! value is H5P_DEFAULT_F (6)
END SUBROUTINE h5dcreate_f
</pre>
<!--<dt><strong>Non-C API(s):</strong>
<dd>
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Dextend" -->
<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.
<p>
Space on disk is immediately allocated for the new dataset extent
if the dataset's space allocation time is set to
<code>H5D_ALLOC_TIME_EARLY</code>.
Fill values will be written to the dataset if the dataset's fill time
is set to <code>H5D_FILL_TIME_IFSET</code> or
<code>H5D_FILL_TIME_ALLOC</code>.
(Also see
<a href="RM_H5P.html#Property-SetFillTime">H5Pset_fill_time</a>
and
<a href="RM_H5P.html#Property-SetAllocTime">H5Pset_alloc_time</a>.)
<dt><strong>Parameters:</strong>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em> <code>dataset_id</code></td>
<td valign="top">IN: Identifier of the dataset.</td></tr>
<tr>
<td valign="top"><em>const&nbsp;hsize_t&nbsp;*</em>&nbsp;<code>size&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Array containing the new magnitude of each dimension.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dextend_f
<dd>
<pre>
SUBROUTINE h5dextend_f(dataset_id, size, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dataset_id ! Dataset identifier
INTEGER(HSIZE_T), DIMENSION(*), INTENT(IN) :: size
! Array containing
! dimensions' sizes
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dextend_f
</pre>
<!--<dt><strong>Non-C API(s):</strong>
<dd>
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Dfill" -->
<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-Fill">H5Dfill</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t </em><code>H5Dfill</code>(
<em>const void *</em><code>fill</code>,
<em>hid_t </em><code>fill_type_id</code>,
<em>void *</em><code>buf</code>,
<em>hid_t </em><code>buf_type_id</code>,
<em>hid_t </em><code>space_id</code>
)
<dt><strong>Purpose:</strong>
<dd>Fills dataspace elements with a fill value in a memory buffer.
<dt><strong>Description:</strong>
<dd><code>H5Dfill</code> explicitly fills
the dataspace selection in memory, <code>space_id</code>,
with the fill value specified in <code>fill</code>.
If <code>fill</code> is <code>NULL</code>,
a fill value of <code>0</code> (zero) is used.
<p>
<code>fill_type_id</code> specifies the datatype
of the fill value.<br>
<code>buf</code> specifies the buffer in which
the dataspace elements will be written.<br>
<code>buf_type_id</code> specifies the datatype of
those data elements.
<p>
Note that if the fill value datatype differs
from the memory buffer datatype, the fill value
will be converted to the memory buffer datatype
before filling the selection.
<dt><strong>Note:</strong>
<dd>Applications sometimes write data only to portions of
an allocated dataset. It is often useful in such cases
to fill the unused space with a known
<span class="termEmphasis">fill value</span>.
See <a href="RM_H5P.html#Property-SetFillValue">H5Pset_fill_value</a>
for further discussion.
Other related functions include
<a href="RM_H5P.html#Property-GetFillValue">H5Pget_fill_value</a>,
<a href="RM_H5P.html#Property-FillValueDefined">H5Pfill_value_defined</a>,
<a href="RM_H5P.html#Property-SetFillTime">H5Pset_fill_time</a>,
<a href="RM_H5P.html#Property-GetFillTime">H5Pget_fill_time</a>,
and
<a href="#Dataset-Create">H5Dcreate</a>.
<dt><strong>Parameters:</strong>
<ul><table>
<tr>
<td valign="top"><em>const void *</em><code>fill</code></td>
<td valign="top">IN: Pointer to the fill value to be used.</td></tr>
<tr>
<td valign="top"><em>hid_t&nbsp;</em><code>fill_type_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Fill value datatype identifier.</td></tr>
<tr>
<td valign="top"><em>void *</em><code>buf</code></td>
<td valign="top">IN/OUT: Pointer to the memory buffer containing the
selection to be filled.</td></tr>
<tr>
<td valign="top"><em>hid_t </em><code>buf_type_id</code></td>
<td valign="top">IN: Datatype of dataspace elements to be filled.</td></tr>
<tr>
<td valign="top"><em>hid_t </em><code>space_id</code></td>
<td valign="top">IN: Dataspace describing memory buffer and
containing the selection to be filled.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dfill_f
<dd>
<pre>
SUBROUTINE h5dfill_f(fill_value, space_id, buf, hdferr)
IMPLICIT NONE
TYPE, INTENET(IN) :: fill_value ! Fill value; may be have one of the
! following types:
! INTEGER, REAL, DOUBLE PRECISION,
! CHARACTER
INTEGER(HID_T), INTENT(IN) :: space_id ! Memory dataspace selection identifier
TYPE, DIMENSION(*) :: buf ! Memory buffer to fill in; must have
! the same datatype as fill value
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dfill_f
</pre>
<!--<dt><strong>Non-C API(s):</strong>
<dd>
<img src="Graphics/Java.gif">
<img src="Graphics/C++.gif">
-->
</dl>
<!-- NEW PAGE -->
<!-- HEADER RIGHT "H5Dget_create_plist" -->
<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>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>dataset_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataset to query.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a dataset creation property list identifier if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dget_create_plist_f
<dd>
<pre>
SUBROUTINE h5dget_create_plist_f(dataset_id, creation_prp, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dataset_id ! Dataset identifier
INTEGER(HID_T), INTENT(OUT) :: creation_id ! Dataset creation
! property list identifier
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dget_create_plist_f
</pre>
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<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-GetOffset">H5Dget_offset</a>
<dt><strong>Signature:</strong>
<dd><em>haddr_t </em><code>H5Dget_offset</code>(<em>hid_t </em><code>dset_id</code>)
<dt><strong>Purpose:</strong>
<dd>Returns dataset address in file.
<dt><strong>Description:</strong>
<dd><code>H5Dget_offset</code> returns the address in the file
of the dataset <code>dset_id</code>.
That address is expressed as the offset in bytes from
the beginning of the file.
<dt><strong>Parameters:</strong>
<ul><table>
<tr>
<td valign="top"><em>hid_t&nbsp;</em><code>dset_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">Dataset identifier.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns the offset in bytes;
otherwise returns <code>HADDR_UNDEF</code>, a negative value.
<dt><strong>Fortran90 Interface:</strong>
<dd>None.
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</pre>
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<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>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>dataset_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataset to query.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a dataspace identifier if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dget_space_f
<dd>
<pre>
SUBROUTINE h5dget_space_f(dataset_id, dataspace_id, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dataset_id ! Dataset identifier
INTEGER(HID_T), INTENT(OUT) :: dataspace_id ! Dataspace identifier
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dget_space_f
</pre>
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<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-GetSpaceStatus">H5Dget_space_status</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5Dget_space_status</code>(<em>hid_t </em><code>dset_id</code>,
<em>H5D_space_status_t *</em><code>status</code>)
<dt><strong>Purpose:</strong>
<dd>Determines whether space has been allocated for a dataset.
<dt><strong>Description:</strong>
<dd><code>H5Dget_space_status</code> determines whether space has been
allocated for the dataset <code>dset_id</code>.
<p>
Space allocation status is returned in <code>status</code>,
which will have one of the following values:
<center>
<table border="0">
<tr valign="top"><td rowspan="3">&nbsp;&nbsp;&nbsp;&nbsp;</td><td>
<code>H5D_SPACE_STATUS_NOT_ALLOCATED</code>
</td><td>
Space has not been allocated for this dataset.
</td></tr><tr valign="top"><td>
<code>H5D_SPACE_STATUS_ALLOCATED</code>
</td><td>
Space has been allocated for this dataset.
</td></tr><tr valign="top"><td>
<code>H5D_SPACE_STATUS_PART_ALLOCATED</code>&nbsp;&nbsp;
</td><td>
Space has been partially allocated for this dataset.
(Used only for datasets with chunked storage.)
</td></tr>
</table>
</center>
<dt><strong>Parameters:</strong>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em> <code>dset_id</code></td>
<td valign="top">IN: Identifier of the dataset to query.</td></tr>
<tr>
<td valign="top"><em>H5D_space_status_t&nbsp;*</em><code>status&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">OUT: Space allocation status.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dget_space_status_f
<dd>
<pre>
SUBROUTINE h5dget_space_status_f(dset_id, flag, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dset_id ! Dataset identifier
INTEGER, INTENET(OUT) :: flag ! Status flag ; possible values:
! H5D_SPACE_STS_ERROR_F
! H5D_SPACE_STS_NOT_ALLOCATED_F
! H5D_SPACE_STS_PART_ALLOCATED_F
! H5D_SPACE_STS_ALLOCATED_F
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dget_space_status_f
</pre>
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<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>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>dataset_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataset to query.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns the amount of storage space allocated for the dataset,
not counting meta data;
otherwise returns 0 (zero).
<dt><strong>Fortran90 Interface:</strong> h5dget_storage_size_f
<dd>
<pre>
SUBROUTINE h5dget_storage_size_f(dset_id, size, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dset_id ! Dataset identifier
INTEGER(HSIZE_T), INTENT(OUT) :: size ! Amount of storage required
! for dataset
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dget_storage_size_f
</pre>
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<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>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>dataset_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataset to query.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a datatype identifier if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dget_type_f
<dd>
<pre>
SUBROUTINE h5dget_type_f(dataset_id, datatype_id, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dataset_id ! Dataset identifier
INTEGER(HID_T), INTENT(OUT) :: datatype_id ! Datatype identifier
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dget_type_f
</pre>
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<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>
<ul><table>
<tr>
<td valign="top"><em>void *</em><code>buf</code></td>
<td valign="top">IN/OUT: Pointer to the buffer in memory containing the
elements to iterate over.</td></tr>
<tr>
<td valign="top"><em>hid_t </em><code>type_id</code></td>
<td valign="top">IN: Datatype identifier for the elements stored in
<code>buf</code>.</td></tr>
<tr>
<td valign="top"><em>hid_t </em><code>space_id</code></td>
<td valign="top">IN: Dataspace identifier for <code>buf</code>.
Also contains the selection to iterate over.</td></tr>
<tr>
<td valign="top"><em>H5D_operator_t&nbsp;</em><code>operator&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Function pointer to the routine to be called
for each element in <code>buf</code> iterated over.</td></tr>
<tr>
<td valign="top"><em>void *</em><code>operator_data</code></td>
<td valign="top">IN/OUT: Pointer to any user-defined data associated
with the operation.</td></tr>
</table></ul>
<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>Fortran90 Interface:</strong>
<dd>None.
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<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>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em> <code>loc_id</code></td>
<td valign="top">IN: Identifier of the file or group
within which the dataset to be accessed will be found.</td></tr>
<tr>
<td valign="top"><em>const&nbsp;char&nbsp;*</em>&nbsp;<code>name&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: The name of the dataset to access.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a dataset identifier if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dopen_f
<dd>
<pre>
SUBROUTINE h5dopen_f(loc_id, name, dset_id, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: loc_id ! File or group identifier
CHARACTER(LEN=*), INTENT(IN) :: name ! Name of the dataset
INTEGER(HID_T), INTENT(OUT) :: dset_id ! Dataset identifier
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dopen_f
</pre>
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<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 a dataset into a buffer.
<dt><strong>Description:</strong>
<dd><code>H5Dread</code> reads a (partial) dataset, specified by its
identifier <code>dataset_id</code>, from the
file into an 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> is used to specify only the selection within
the file dataset's dataspace. Any dataspace specified in <code>file_space_id</code>
is ignored by the library and the dataset's dataspace is always used.
<code>file_space_id</code> can be the constant <code>H5S_ALL</code>.
which indicates that the entire file dataspace, as defined by the
current dimensions of the dataset, is to be selected.
<p>
<code>mem_space_id</code> is used to specify both the memory dataspace
and the selection within that dataspace.
<code>mem_space_id</code> can be the constant <code>H5S_ALL</code>,
in which case the file dataspace is used for the memory dataspace and
the selection defined with <code>file_space_id</code> is used for the
selection within that dataspace.
<p>
If raw data storage space has not been allocated for the dataset
and a fill value has been defined, the returned buffer <code>buf</code>
is filled with the fill value.
<p>
The behavior of the library for the various combinations of valid
dataspace identifiers and H5S_ALL for the <code>mem_space_id</code> and the
<code>file_space_id</code> parameters is described below:
<br><br>
<table border=0>
<tr>
<th>
<code>mem_space_id&nbsp;&nbsp;</code>
</th>
<th>
<code>file_space_id&nbsp;&nbsp;</code>
</th>
<th>
Behavior
</th>
</tr>
<tr valign="top">
<td>
valid dataspace identifier
</td>
<td>
valid dataspace identifier
</td>
<td>
<code>mem_space_id</code> specifies the memory dataspace and the
selection within it.
<code>file_space_id</code> specifies the selection within the file
dataset's dataspace.
</td>
</tr>
<tr valign="top">
<td>
<code>H5S_ALL</code>
</td>
<td>
valid dataspace identifier
</td>
<td>
The file dataset's dataspace is used for the memory dataspace and the
selection specified with <code>file_space_id</code> specifies the
selection within it.
The combination of the file dataset's dataspace and the selection from
<code>file_space_id</code> is used for memory also.
</td>
</tr>
<tr valign="top">
<td>
valid dataspace identifier
</td>
<td>
<code>H5S_ALL</code>
</td>
<td>
<code>mem_space_id</code> specifies the memory dataspace and the
selection within it.
The selection within the file dataset's dataspace is set to the "all"
selection.
</td>
</tr>
<tr valign="top">
<td>
<code>H5S_ALL</code>
</td>
<td>
<code>H5S_ALL</code>
</td>
<td>
The file dataset's dataspace is used for the memory dataspace and the
selection within the memory dataspace is set to the "all" selection.
The selection within the file dataset's dataspace is set to the "all"
selection.
</td>
</tr>
</table>
<p>
Setting an <code>H5S_ALL</code> selection indicates that the entire dataspace, as
defined by the current dimensions of a dataspace, will be selected.
The number of elements selected in the memory dataspace must match the
number of elements selected in the file dataspace.
<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>
Data is automatically converted from the file datatype
and dataspace to the memory datatype and dataspace
at the time of the read. 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>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em> <code>dataset_id</code></td>
<td valign="top">IN: Identifier of the dataset read from.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>mem_type_id</code></td>
<td valign="top">IN: Identifier of the memory datatype.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>mem_space_id</code></td>
<td valign="top">IN: Identifier of the memory dataspace.</td></tr>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>file_space_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataset's dataspace in the file.</td></tr>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>xfer_plist_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of a transfer property list
for this I/O operation.</td></tr>
<tr>
<td valign="top"><em>void *</em> <code>buf</code></td>
<td valign="top">OUT: Buffer to receive data read from file.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dread_f
<dd>
<pre>
SUBROUTINE h5dread_f(dset_id, mem_type_id, buf, dims, hdferr, &amp;
mem_space_id, file_space_id, xfer_prp)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dset_id ! Dataset identifier
INTEGER(HID_T), INTENT(IN) :: mem_type_id ! Memory datatype identifier
TYPE, INTENT(INOUT) :: buf ! Data buffer; may be a scalar
! or an array
DIMENSION(*), INTEGER(HSIZE_T), INTENT(IN) :: dims
! Array to hold corresponding
! dimension sizes of data
! buffer buf
! dim(k) has value of the k-th
! dimension of buffer buf
! Values are ignored if buf is
! a scalar
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
INTEGER(HID_T), OPTIONAL, INTENT(IN) :: mem_space_id
! Memory dataspace identfier
! Default value is H5S_ALL_F
INTEGER(HID_T), OPTIONAL, INTENT(IN) :: file_space_id
! File dataspace identfier
! Default value is H5S_ALL_F
INTEGER(HID_T), OPTIONAL, INTENT(IN) :: xfer_prp
! Transfer property list identifier
! Default value is H5P_DEFAULT_F
END SUBROUTINE h5dread_f
</pre>
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<hr>
<dl>
<dt><strong>Name:</strong> <a name="Dataset-VLGetBuf">H5Dvlen_get_buf_size</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t </em><code>H5Dvlen_get_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>H5Dvlen_get_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
required to store the VL data in memory.
<dt><strong>Parameters:</strong>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>dataset_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataset to query.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>type_id</code></td>
<td valign="top">IN: Datatype identifier.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>space_id</code></td>
<td valign="top">IN: Dataspace identifier.</td></tr>
<tr>
<td valign="top"><em>hsize_t</em> *<code>size</code></td>
<td valign="top">OUT: The size in bytes of the memory
buffer required to store the VL data.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dvlen_get_max_len_f
<dd>There is no direct FORTRAN couterpart for the C function
<code>H5Dvlen_get_buf_size</code>;
corresponding functionality is provided by the FORTRAN function
<code>h5dvlen_get_max_len_f</code></a>.
<br>
<pre>
SUBROUTINE h5dvlen_get_max_len_f(dset_id, size, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dset_id ! Dataset identifier
INTEGER(HID_T), INTENT(IN) :: type_id ! Datatype identifier
INTEGER(HID_T), INTENT(IN) :: space_id ! Dataspace identifier
INTEGER(SIZE_T), INTENT(OUT) :: elem_len ! Maximum length of the element
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5dvlen_get_max_len_f
</pre>
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<!-- HEADER RIGHT "H5Dvlen_reclaim" -->
<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>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em> <code>type_id</code></td>
<td valign="top">IN: Identifier of the datatype.</td></tr>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>space_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataspace.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>plist_id</code></td>
<td valign="top">IN: Identifier of the property list used to create the buffer.</td></tr>
<tr>
<td valign="top"><em>void</em> *<code>buf</code></td>
<td valign="top">IN: Pointer to the buffer to be reclaimed.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong>
<dd>None.
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SUBROUTINE
</pre>
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<!-- HEADER RIGHT "H5Dwrite" -->
<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 a buffer to a dataset.
<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> is used to specify only the selection within
the file dataset's dataspace. Any dataspace specified in <code>file_space_id</code>
is ignored by the library and the dataset's dataspace is always used.
<code>file_space_id</code> can be the constant <code>H5S_ALL</code>.
which indicates that the entire file dataspace, as defined by the
current dimensions of the dataset, is to be selected.
<p>
<code>mem_space_id</code> is used to specify both the memory dataspace
and the selection within that dataspace.
<code>mem_space_id</code> can be the constant <code>H5S_ALL</code>,
in which case the file dataspace is used for the memory dataspace and
the selection defined with <code>file_space_id</code> is used for the
selection within that dataspace.
<p>
The behavior of the library for the various combinations of valid
dataspace IDs and H5S_ALL for the <code>mem_space_id</code> and the
<code>file_space_id</code> parameters is described below:
<br><br>
<table border=0>
<tr>
<th>
<code>mem_space_id&nbsp;&nbsp;</code>
</th>
<th>
<code>file_space_id&nbsp;&nbsp;</code>
</th>
<th>
Behavior
</th>
</tr>
<tr valign="top">
<td>
valid dataspace identifier
</td>
<td>
valid dataspace identifier
</td>
<td>
<code>mem_space_id</code> specifies the memory dataspace and the
selection within it.
<code>file_space_id</code> specifies the selection within the file
dataset's dataspace.
</td>
</tr>
<tr valign="top">
<td>
H5S_ALL
</td>
<td>
valid dataspace identifier
</td>
<td>
The file dataset's dataspace is used for the memory dataspace and the
selection specified with <code>file_space_id</code> specifies the
selection within it.
The combination of the file dataset's dataspace and the selection from
<code>file_space_id</code> is used for memory also.
</td>
</tr>
<tr valign="top">
<td>
valid dataspace identifier
</td>
<td>
H5S_ALL
</td>
<td>
<code>mem_space_id</code> specifies the memory dataspace and the
selection within it.
The selection within the file dataset's dataspace is set to the "all"
selection.
</td>
</tr>
<tr valign="top">
<td>
H5S_ALL
</td>
<td>
H5S_ALL
</td>
<td>
The file dataset's dataspace is used for the memory dataspace and the
selection within the memory dataspace is set to the "all" selection.
The selection within the file dataset's dataspace is set to the "all"
selection.
</td>
</tr>
</table>
<p>
Setting an "all" selection indicates that the entire dataspace, as
defined by the current dimensions of a dataspace, will be selected.
The number of elements selected in the memory dataspace must match the
number of elements selected in the file dataspace.
<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 dataset will fail if the HDF5 file was
not opened with write access permissions.
<p>
Data is automatically converted from the memory datatype
and dataspace to the file datatype and dataspace
at the time of the write. 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.
<p>
If the dataset's space allocation time is set to
<code>H5D_ALLOC_TIME_LATE</code> or <code>H5D_ALLOC_TIME_INCR</code>
and the space for the dataset has not yet been allocated,
that space is allocated when the first raw data is written to the
dataset.
Unused space in the dataset will be written with fill values at the
same time if the dataset's fill time is set to
<code>H5D_FILL_TIME_IFSET</code> or <code>H5D_FILL_TIME_ALLOC</code>.
(Also see
<a href="RM_H5P.html#Property-SetFillTime">H5Pset_fill_time</a>
and
<a href="RM_H5P.html#Property-SetAllocTime">H5Pset_alloc_time</a>.)
<p>
If a dataset's storage layout is 'compact', care must be taken when
writing data to the dataset in parallel. A compact dataset's raw data
is cached in memory and may be flushed to the file from any of the
parallel processes, so parallel applications should always attempt to
write identical data to the dataset from all processes.
<dt><strong>Parameters:</strong>
<ul><table>
<tr>
<td valign="top"><em>hid_t</em> <code>dataset_id</code></td>
<td valign="top">IN: Identifier of the dataset to write to.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>mem_type_id</code></td>
<td valign="top">IN: Identifier of the memory datatype.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>mem_space_id</code></td>
<td valign="top">IN: Identifier of the memory dataspace.</td></tr>
<tr>
<td valign="top"><em>hid_t</em>&nbsp;<code>file_space_id&nbsp;&nbsp;&nbsp;&nbsp;</code></td>
<td valign="top">IN: Identifier of the dataset's dataspace in the file.</td></tr>
<tr>
<td valign="top"><em>hid_t</em> <code>xfer_plist_id</code></td>
<td valign="top">IN: Identifier of a transfer property list
for this I/O operation.</td></tr>
<tr>
<td valign="top"><em>const void *</em> <code>buf</code></td>
<td valign="top">IN: Buffer with data to be written to the file.</td></tr>
</table></ul>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
<dt><strong>Fortran90 Interface:</strong> h5dwrite_f
<dd>
<pre>
SUBROUTINE h5dwrite_f(dset_id, mem_type_id, buf, dims, hdferr, &amp;
mem_space_id, file_space_id, xfer_prp)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: dset_id ! Dataset identifier
INTEGER(HID_T), INTENT(IN) :: mem_type_id ! Memory datatype identifier
TYPE, INTENT(IN) :: buf ! Data buffer; may be a scalar
! or an array</pre>
<!-- NEW PAGE -->
<pre>
DIMENSION(*), INTEGER(HSIZE_T), INTENT(IN) :: dims
! Array to hold corresponding
! dimension sizes of data
! buffer buf; dim(k) has value
! of the k-th dimension of
! buffer buf; values are
! ignored if buf is a scalar
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
INTEGER(HID_T), OPTIONAL, INTENT(IN) :: mem_space_id
! Memory dataspace identfier
! Default value is H5S_ALL_F
INTEGER(HID_T), OPTIONAL, INTENT(IN) :: file_space_id
! File dataspace identfier
! Default value is H5S_ALL_F
INTEGER(HID_T), OPTIONAL, INTENT(IN) :: xfer_prp
! Transfer property list
! identifier; default value
! is H5P_DEFAULT_F
END SUBROUTINE h5dwrite_f
</pre>
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