<html> <head><title> HDF5/H5S Draft API Specification </title></head> <body> <hr> <center> <a href="RM_H5Front.html">HDF5 Reference Manual</a> <a href="RM_H5.html">H5</a> <a href="RM_H5A.html">H5A</a> <a href="RM_H5D.html">H5D</a> <a href="RM_H5E.html">H5E</a> <a href="RM_H5F.html">H5F</a> <a href="RM_H5G.html">H5G</a> <a href="RM_H5P.html">H5P</a> H5S <a href="RM_H5T.html">H5T</a> <a href="RM_H5Z.html">H5Z</a> <a href="Glossary.html">Glossary</a> </center> <hr> <center> <h1>H5S: Dataspace Interface</h1> </center> <h2>Dataspace Object API Functions</h2> These functions create and manipulate the dataspace in which to store the elements of a dataset. <table border=0> <tr><td valign=top> <ul> <li><a href="#Dataspace-Create">H5Screate</a> <li><a href="#Dataspace-CreateSimple">H5Screate_simple</a> <li><a href="#Dataspace-Copy">H5Scopy</a> <li><a href="#Dataspace-SelectNpoints">H5Sselect_npoints</a> <li><a href="#Dataspace-SelectElements">H5Sselect_elements</a> </ul> </td><td> </td><td valign=top> <ul> <li><a href="#Dataspace-ExtentNpoints">H5Sextent_npoints</a> <li><a href="#Dataspace-ExtentNdims">H5Sextent_ndims</a> <li><a href="#Dataspace-ExtentDims">H5Sextent_dims</a> <li><a href="#Dataspace-GetClass">H5Sget_class</a> </ul> </td><td> </td><td valign=top> <ul> <li><a href="#Dataspace-SetExtentSimple">H5Sset_extent_simple</a> <li><a href="#Dataspace-IsSimple">H5Sis_simple</a> <li><a href="#Dataspace-SelectHyperslab">H5Sselect_hyperslab</a> <li><a href="#Dataspace-Close">H5Sclose</a> </ul> </td></tr> </table> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-Create">H5Screate</a> <dt><strong>Signature:</strong> <dd><em>hid_t</em> <code>H5Screate</code>(<em>H5S_class_t</em> <code>type</code>) <dt><strong>Purpose:</strong> <dd>Creates a new dataspace of a specified type. <dt><strong>Description:</strong> <dd><code>H5Screate</code> creates a new dataspace of a particular <code>type</code>. The types currently supported are <code>H5S_SCALAR</code>, <code>H5S_SIMPLE</code>, and <code>H5S_NONE</code>; others are planned to be added later. The <code>H5S_NONE</code> dataspace can only hold a selection, not an extent. <dt><strong>Parameters:</strong> <dl> <dt><em>H5S_class_t</em> <code>type</code> <dd>The type of dataspace to be created. </dl> <dt><strong>Returns:</strong> <dd>Returns a dataspace identifier if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-CreateSimple">H5Screate_simple</a> <dt><strong>Signature:</strong> <dd><em>hid_t</em> <code>H5Screate_simple</code>(<em>int</em> <code>rank</code>, <em>const hsize_t *</em> <code>dims</code>, <em>const hsize_t *</em> <code>maxdims</code> ) <dt><strong>Purpose:</strong> <dd>Creates a new simple data space and opens it for access. <dt><strong>Description:</strong> <dd><code>H5Screate_simple</code> creates a new simple data space and opens it for access. The <code>rank</code> is the number of dimensions used in the dataspace. The <code>dims</code> argument is the size of the simple dataset and the <code>maxdims</code> argument is the upper limit on the size of the dataset. <code>maxdims</code> may be the null pointer in which case the upper limit is the same as <code>dims</code>. If an element of <code>maxdims</code> is zero then the corresponding dimension is unlimited, otherwise no element of <code>maxdims</code> should be smaller than the corresponding element of <code>dims</code>. The dataspace identifier returned from this function should be released with <code>H5Sclose</code> or resource leaks will occur. <dt><strong>Parameters:</strong> <dl> <dt><em>int</em> <code>rank</code> <dd>Number of dimensions of dataspace. <dt><em>const hsize_t *</em> <code>dims</code> <dd>An array of the size of each dimension. <dt><em>const hsize_t *</em> <code>maxdims</code> <dd>An array of the maximum size of each dimension. </dl> <dt><strong>Returns:</strong> <dd>Returns a dataspace identifier if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-Copy">H5Scopy</a> <dt><strong>Signature:</strong> <dd><em>hid_t </em><code>H5Scopy</code>(<em>hid_t </em><code>space_id</code> ) <dt><strong>Purpose:</strong> <dd>Creates an exact copy of a dataspace. <dt><strong>Description:</strong> <dd><code>H5Scopy</code> creates a new dataspace which is an exact copy of the dataspace identified by <code>space_id</code>. The dataspace identifier returned from this function should be released with <code>H5Sclose</code> or resource leaks will occur. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>Identifier of dataspace to copy. </dl> <dt><strong>Returns:</strong> <dd>Returns a dataspace identifier if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-SelectElements">H5Sselect_elements</a> <dt><strong>Signature:</strong> <dd><em>herr_t</em> <code>H5Sselect_elements</code>(<em>hid_t </em><code>space_id</code>, <em>dh5s_selopt_t</em> <code>op</code>, <em>const size_t</em> <code>num_elements</code>, <em>const hssize_t *</em><code>coord</code>[ ] ) <dt><strong>Purpose:</strong> <dd>Selects array elements to be included in the selection for a dataspace. <dt><strong>Description:</strong> <dd><code>H5Sselect_elements</code> selects array elements to be included in the selection for the <code>space_id</code> dataspace. The number of elements selected must be set with the <code>num_elements</code>. The <code>coord</code> array is a two-dimensional array of size <em>dataspace rank</em> by <code>num_elements</code> (ie. a list of coordinates in the array). The order of the element coordinates in the <code>coord</code> array also specifies the order in which the array elements are iterated through when I/O is performed. Duplicate coordinate locations are not checked for. <P> The selection operator <code>op</code> determines how the new selection is to be combined with the previously existing selection for the dataspace. Currently, only the <code>H5S_SELECT_SET</code> operator is supported, which replaces the existing selection with the parameters from this call. When operators other than <code>H5S_SELECT_SET</code> are used to combine a new selection with an existing selection, the selection ordering is reset to 'C' array ordering. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>Identifier of the dataspace. <dt><em>dh5s_selopt_t</em> <code>op</code> <dd>operator specifying how the new selection is to be combined with the existing selection for the dataspace. <dt><em>const size_t</em> <code>num_elements</code> <dd>Number of elements to be selected. <dt><em>const hssize_t *</em><code>coord</code>[ ] <dd>A 2-dimensional array specifying the coordinates of the elements being selected. </dl> <dt><strong>Returns:</strong> <dd>Returns SUCCEED (0) if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-ExtentNpoints">H5Sextent_npoints</a> <dt><strong>Signature:</strong> <dd><em>hsize_t</em> <code>H5Sextent_npoints</code>(<em>hid_t </em><code>space_id</code>) <dt><strong>Purpose:</strong> <dd>Determines the number of elements in a dataspace. <dt><strong>Description:</strong> <dd><code>H5Sextent_npoints</code> determines the number of elements in a dataspace. For example, a simple 3-dimensional dataspace with dimensions 2, 3, and 4 would have 24 elements. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>ID of the dataspace object to query </dl> <dt><strong>Returns:</strong> <dd>Returns the number of elements in the dataspace if successful; otherwise returns 0. </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-SelectNpoints">H5Sselect_npoints</a> <dt><strong>Signature:</strong> <dd><em>hsize_t</em> <code>H5Sselect_npoints</code>(<em>hid_t</em> <code>space_id</code>) <dt><strong>Purpose:</strong> <dd>Determines the number of elements in a dataspace. <dt><strong>Description:</strong> <dd><code>H5Sselect_npoints</code> determines the number of elements in the current selection of a dataspace. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>Dataspace identifier. </dl> <dt><strong>Returns:</strong> <dd>Returns a dataspace identifier if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-ExtentNdims">H5Sextent_ndims</a> <dt><strong>Signature:</strong> <dd><em>int</em> <code>H5Sextent_ndims</code>(<em>hid_t</em> <code>space_id</code>) <dt><strong>Purpose:</strong> <dd>Determines the dimensionality of a dataspace. <dt><strong>Description:</strong> <dd><code>H5Sextent_ndims</code> determines the dimensionality (or rank) of a dataspace. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>Identifier of the dataspace </dl> <dt><strong>Returns:</strong> <dd>Returns the number of dimensions in the dataspace if successful; otherwise FAIL (-1) </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-ExtentDims">H5Sextent_dims</a> <dt><strong>Signature:</strong> <dd><em>int</em> <code>H5Sextent_dims</code>(<em>hid_t</em> <code>space_id</code>, <em>hsize_t *</em><code>dims</code>, <em>hsize_t *</em><code>maxdims</code> ) <dt><strong>Purpose:</strong> <dd>Retrieves dataspace dimension size and maximum size. <dt><strong>Description:</strong> <dd><code>H5Sextent_dims</code> returns the size and maximum sizes of each dimension of a dataspace through the <code>dims</code> and <code>maxdims</code> parameters. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>IN: Identifier of the dataspace object to query <dt><em>hsize_t *</em><code>dims</code> <dd>OUT: Pointer to array to store the size of each dimension. <dt><em>hsize_t *</em><code>maxdims</code> <dd>OUT: Pointer to array to store the maximum size of each dimension. </dl> <dt><strong>Returns:</strong> <dd>Returns the number of dimensions in the dataspace if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-SetExtentSimple">H5Sset_extent_simple</a> <dt><strong>Signature:</strong> <dd><em>herr_t</em> <code>H5S_set_extent_simple</code>(<em>hid_t</em> <code>space_id</code>, <em>int</em> <code>rank</code>, <em>const hsize_t *</em><code>current_size</code>, <em>const hsize_t *</em><code>maximum_size</code> ) <dt><strong>Purpose:</strong> <dd>Sets or resets the size of an existing dataspace. <dt><strong>Description:</strong> <dd><code>H5S_set_extent_simple</code> sets or resets the size of an existing dataspace. <p> <code>rank</code> is the dimensionality, or number of dimensions, of the dataspace. <p> <code>current_size</code> is an array of size <code>rank</code> which contains the new size of each dimension in the dataspace. <code>maximum_size</code> is an array of size <code>rank</code> which contains the maximum size of each dimension in the dataspace. <p> Any previous extent is removed from the dataspace, the dataspace type is set to <code>H5S_SIMPLE</code>, and the extent is set as specified. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>Dataspace identifier. <dt><em>int</em> <code>rank</code> <dd>Rank, or dimensionality, of the dataspace. <dt><em>const hsize_t *</em><code>current_size</code> <dd>Array containing current size of dataspace. <dt><em>const hsize_t *</em><code>maximum_size</code> <dd>Array containing maximum size of dataspace. </dl> <dt><strong>Returns:</strong> <dd>Returns a dataspace identifier if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-IsSimple">H5Sis_simple</a> <dt><strong>Signature:</strong> <dd><em>hbool_t </em><code>H5Sis_simple</code>(<em>hid_t </em><code>space_id</code>) <dt><strong>Purpose:</strong> <dd>Determines whether a dataspace is a simple dataspace. <dt><strong>Description:</strong> <dd><code>H5Sis_simple</code> determines whether a dataspace is a simple dataspace. [Currently, all dataspace objects are simple dataspaces, complex dataspace support will be added in the future] <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>Identifier of the dataspace to query </dl> <dt><strong>Returns:</strong> <dd>Returns TRUE or FALSE if Successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-GetClass">H5Sget_class</a> <dt><strong>Signature:</strong> <dd><em>H5S_class_t</em> <code>H5Sget_class</code>(<em>hid_t</em> <code>space_id</code>) <dt><strong>Purpose:</strong> <dd>Determine the current class of a dataspace. <dt><strong>Description:</strong> <dd><code>H5Sget_class</code> queries a dataspace to determine the current class of a dataspace. <p> The function returns a class name, one of the following: <code>H5S_SCALAR</code>, <code>H5S_SIMPLE</code>, or <code>H5S_NONE</code>. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>Dataspace identifier. </dl> <dt><strong>Returns:</strong> <dd>Returns a dataspace class name if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-SelectHyperslab">H5Sselect_hyperslab</a> <dt><strong>Signature:</strong> <dd><em>herr_t</em> <code>H5Sselect_hyperslab</code>(<em>hid_t</em> <code>space_id</code>, <em>h5s_selopt_t</em><code>op</code>, <em>const hssize_t *</em><code>start</code>, <em>const hsize_t *</em><code>stride</code> <em>const hsize_t *</em><code>count</code>, <em>const hsize_t *</em><code>block</code> ) <dt><strong>Purpose:</strong> <dd>Selects a hyperslab region to add to the current selected region. <dt><strong>Description:</strong> <dd><code>H5Sselect_hyperslab</code> selects a hyperslab region to add to the current selected region for the dataspace specified by <code>space_id</code>. <p> The <code>start</code>, <code>stride</code>, <code>count</code>, and <code>block</code> arrays must be the same size as the rank of the dataspace. <p> The selection operator <code>op</code> determines how the new selection is to be combined with the already existing selection for the dataspace. <p> Currently, only the <code>H5S_SELECT_SET</code> operator is supported; it replaces the existing selection with the parameters from this call. Overlapping blocks are not supported with the <code>H5S_SELECT_SET</code> operator. <P> The <code>start</code> array determines the starting coordinates of the hyperslab to select. <p> The <code>stride</code> array chooses array locations from the dataspace with each value in the <code>stride</code> array determining how many elements to move in each dimension. Setting a value in the <code>stride</code> array to 1 moves to each element in that dimension of the dataspace; setting a value of 2 in a location in the <code>stride</code> array moves to every other element in that dimension of the dataspace. In other words, the <code>stride</code> determines the number of elements to move from the <code>start</code> location in each dimension. Stride values of 0 are not allowed. If the <code>stride</code> parameter is <code>NULL</code>, a contiguous hyperslab is selected (as if each value in the <code>stride</code> array was set to all 1's). <p> The <code>count</code> array determines how many blocks to select from the dataspace, in each dimension. <p> The <code>block</code> array determines the size of the element block selected from the dataspace. If the <code>block</code> parameter is set to <code>NULL</code>, the block size defaults to a single element in each dimension (as if the <code>block</code> array was set to all 1's). <P> For example, in a 2-dimensional dataspace, setting <code>start</code> to [1,1], <code>stride</code> to [4,4], <code>count</code> to [3,7], and <code>block</code> to [2,2] selects 21 2x2 blocks of array elements starting with location (1,1) and selecting blocks at locations (1,1), (5,1), (9,1), (1,5), (5,5), etc. <P> Regions selected with this function call default to C order iteration when I/O is performed. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>IN: Identifier of dataspace selection to modify <dt><em>H5S_seloper_t</em> <code>op</code> <dd>IN: Operation to perform on current selection. <dt><em>const hssize_t *</em><code>start</code> <dd>IN: Offset of start of hyperslab <dt><em>const hsize_t *</em><code>count</code> <dd>IN: Number of blocks included in hyperslab. <dt><em>const hsize_t *</em><code>stride</code> <dd>IN: Hyperslab stride. <dt><em>const hsize_t *</em><code>block</code> <dd>IN: Size of block in hyperslab. </dl> <dt><strong>Returns:</strong> <dd>Returns SUCCEED (0) if successful; otherwise FAIL (-1). </dl> <hr> <dl> <dt><strong>Name:</strong> <a name="Dataspace-Close">H5Sclose</a> <dt><strong>Signature:</strong> <dd><em>herr_t </em><code>H5Sclose</code>(<em>hid_t </em><code>space_id</code> ) <dt><strong>Purpose:</strong> <dd>Releases and terminates access to a dataspace. <dt><strong>Description:</strong> <dd><code>H5Sclose</code> releases a dataspace. Further access through the dataspace identifier is illegal. Failure to release a dataspace with this call will result in resource leaks. <dt><strong>Parameters:</strong> <dl> <dt><em>hid_t</em> <code>space_id</code> <dd>Identifier of dataspace to release. </dl> <dt><strong>Returns:</strong> <dd>Returns SUCCEED (0) if successful; otherwise FAIL (-1). </dl> <hr> <center> <a href="RM_H5Front.html">HDF5 Reference Manual</a> <a href="RM_H5.html">H5</a> <a href="RM_H5A.html">H5A</a> <a href="RM_H5D.html">H5D</a> <a href="RM_H5E.html">H5E</a> <a href="RM_H5F.html">H5F</a> <a href="RM_H5G.html">H5G</a> <a href="RM_H5P.html">H5P</a> H5S <a href="RM_H5T.html">H5T</a> <a href="RM_H5Z.html">H5Z</a> <a href="Glossary.html">Glossary</a> </center> <hr> <address> <a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a> <br> Last modified: 14 July 1998 </body> </html>