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HDF5/H5A API Specification
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<h1>H5A: Attribute Interface</h1>
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<h2>Attribute API Functions</h2>

These functions create and manipulate attributes 
and information about attributes.
<br>
In the following lists, italic type indicates a configurable macro.

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

<table border=0>
<tr><td valign=top>
<ul>
    <li><i><a href="#Annot-Create">H5Acreate</a></i>
    <li><a href="#Annot-Create1">H5Acreate1</a>&nbsp;*
    <li><a href="#Annot-Create2">H5Acreate2</a>
    <li><a href="#Annot-CreateByName">H5Acreate_by_name</a>
    <li><a href="#Annot-Open">H5Aopen</a>
    <li><a href="#Annot-OpenByName">H5Aopen_by_name</a>
    <li><a href="#Annot-OpenName">H5Aopen_name</a>&nbsp;*
    <li><a href="#Annot-OpenByIdx">H5Aopen_by_idx</a>   
    <li><a href="#Annot-OpenIdx">H5Aopen_idx</a>&nbsp;*
    <li><a href="#Annot-Exists">H5Aexists</a>
    <li><a href="#Annot-ExistsByName">H5Aexists_by_name</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
    <li><a href="#Annot-Rename">H5Arename</a>
    <li><a href="#Annot-RenameByName">H5Arename_by_name</a>
    <li><a href="#Annot-Write">H5Awrite</a>
    <li><a href="#Annot-Read">H5Aread</a>
    <li><a href="#Annot-Close">H5Aclose</a>
    <li><i><a href="#Annot-Iterate">H5Aiterate</a></i>
    <li><a href="#Annot-Iterate1">H5Aiterate1</a>&nbsp;*
    <li><a href="#Annot-Iterate2">H5Aiterate2</a>
    <li><a href="#Annot-IterateByName">H5Aiterate_by_name</a>
    <li><a href="#Annot-Delete">H5Adelete</a>
    <li><a href="#Annot-DeleteByName">H5Adelete_by_name</a>
    <li><a href="#Annot-DeleteByIdx">H5Adelete_by_idx</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
    <li><a href="#Annot-GetInfo">H5Aget_info</a>   
    <li><a href="#Annot-GetInfoByName">H5Aget_info_by_name</a>   
    <li><a href="#Annot-GetInfoByIdx">H5Aget_info_by_idx</a>   
    <li><a href="#Annot-NumAttrs">H5Aget_num_attrs</a>&nbsp;*
    <li><a href="#Annot-GetName">H5Aget_name</a>
    <li><a href="#Annot-GetCreatePlist">H5Aget_create_plist</a>
    <li><a href="#Annot-GetSpace">H5Aget_space</a>
    <li><a href="#Annot-GetType">H5Aget_type</a>
    <li><a href="#Annot-GetStorageSize">H5Aget_storage_size</a>
    <li><a href="#Annot-GetNameByIdx">H5Aget_name_by_idx</a>   

</ul>
</td></tr>
<tr><td align=right colspan=5>
    *&nbsp;<i>Use of these functions is deprecated in Release 1.8.0.</i>
</td></tr>
</table>
<br>

<i>Alphabetical Listing</i>

<table border="0">
  <tr>
    <td valign="top">
	<ul>
      <li><a href="#Annot-Close">H5Aclose</a>
      <li><i><a href="#Annot-Create">H5Acreate</a></i>
      <li><a href="#Annot-Create1">H5Acreate1</a>&nbsp;*
      <li><a href="#Annot-Create2">H5Acreate2</a>
      <li><a href="#Annot-CreateByName">H5Acreate_by_name</a>
      <li><a href="#Annot-Delete">H5Adelete</a>
      <li><a href="#Annot-DeleteByName">H5Adelete_by_name</a>
      <li><a href="#Annot-DeleteByIdx">H5Adelete_by_idx</a>
      <li><a href="#Annot-Exists">H5Aexists</a>
      <li><a href="#Annot-ExistsByName">H5Aexists_by_name</a>
      <li><a href="#Annot-GetCreatePlist">H5Aget_create_plist</a>
	</ul>      
    </td>
    
    <td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
    
    <td valign="top">
	<ul>
      <li><a href="#Annot-GetInfo">H5Aget_info</a>   
      <li><a href="#Annot-GetInfoByIdx">H5Aget_info_by_idx</a>   
      <li><a href="#Annot-GetInfoByName">H5Aget_info_by_name</a>   
      <li><a href="#Annot-GetName">H5Aget_name</a>
      <li><a href="#Annot-GetNameByIdx">H5Aget_name_by_idx</a>   
      <li><a href="#Annot-NumAttrs">H5Aget_num_attrs</a>&nbsp;*
      <li><a href="#Annot-GetSpace">H5Aget_space</a>
      <li><a href="#Annot-GetStorageSize">H5Aget_storage_size</a>
      <li><a href="#Annot-GetType">H5Aget_type</a>
      <li><i><a href="#Annot-Iterate">H5Aiterate</a></i>
      <li><a href="#Annot-Iterate1">H5Aiterate1</a>&nbsp;*
    </ul>
	</td>
    
    <td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
    
    <td valign="top">
	<ul>
      <li><a href="#Annot-Iterate2">H5Aiterate2</a>
      <li><a href="#Annot-IterateByName">H5Aiterate_by_name</a>
      <li><a href="#Annot-Open">H5Aopen</a>
      <li><a href="#Annot-OpenByIdx">H5Aopen_by_idx</a>   
      <li><a href="#Annot-OpenByName">H5Aopen_by_name</a>   
      <li><a href="#Annot-OpenIdx">H5Aopen_idx</a>&nbsp;*
      <li><a href="#Annot-OpenName">H5Aopen_name</a>&nbsp;*
      <li><a href="#Annot-Read">H5Aread</a>
      <li><a href="#Annot-Rename">H5Arename</a>
      <li><a href="#Annot-RenameByName">H5Arename_by_name</a>
      <li><a href="#Annot-Write">H5Awrite</a>
	</ul>
    </td>
  </tr>
</table>

<!-- NEW PAGE -->
<br>
<strong>The Fortran Interface:</strong>
<br>
In general, each Fortran subroutine performs exactly the same task 
as the corresponding C function.  
<br>

<table border=0>
<tr><td valign=top>
<ul>
    <li><a href="#Annot-Close">h5aclose_f</a>
    <li><a href="#Annot-Create">h5acreate_f</a>
    <li><a href="#Annot-CreateByName">h5acreate_by_name_f</a>
    <li><a href="#Annot-Delete">h5adelete_f</a>
    <li><a href="#Annot-DeleteByName">h5adelete_by_name_f</a>
    <li><a href="#Annot-DeleteByIdx">h5adelete_by_idx_f</a>
    <li><a href="#Annot-Exists">h5aexists_f</a>
    <li><a href="#Annot-ExistsByName">h5aexists_by_name_f</a>
    <li><a href="#Annot-GetCreatePlist">h5aget_create_plist_f</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
    <li><a href="#Annot-GetInfo">h5aget_info_f</a>
    <li><a href="#Annot-GetInfoByIdx">h5aget_info_by_idx_f</a>
    <li><a href="#Annot-GetInfoByName">h5aget_info_by_name_f</a>
    <li><a href="#Annot-GetName">h5aget_name_f</a>
    <li><a href="#Annot-GetNameByIdx">h5aget_name_by_idx_f</a>
    <li><a href="#Annot-NumAttrs">h5aget_num_attrs_f</a>&nbsp;*
    <li><a href="#Annot-GetSpace">h5aget_space_f</a>
    <li><a href="#Annot-GetStorageSize">h5aget_storage_size_f</a>
    <li><a href="#Annot-GetType">h5aget_type_f</a>
</ul>
</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>
<ul>
<!--<li><a href="#Annot-Iterate">h5aiterate_f</a>                -->
    <li><a href="#Annot-Open">h5aopen_f</a>
    <li><a href="#Annot-OpenByIdx">h5aopen_by_idx_f</a>
    <li><a href="#Annot-OpenByName">h5aopen_by_name_f</a>
    <li><a href="#Annot-OpenIdx">h5aopen_idx_f</a>&nbsp;*
    <li><a href="#Annot-OpenName">h5aopen_name_f</a>&nbsp;*
    <li><a href="#Annot-Read">h5aread_f</a>
    <li><a href="#Annot-Rename">h5arename_f</a>
    <li><a href="#Annot-RenameByName">h5arename_by_name_f</a>
    <li><a href="#Annot-Write">h5awrite_f</a>
</ul>
</td></tr>
<tr><td align=right colspan=5>
    *&nbsp;<i>Use of these functions is deprecated in Release 1.8.0.</i>
</td></tr>
</table>


<p>
The Attribute interface, H5A, is primarily designed to easily allow 
small datasets to be attached to primary datasets as metadata information. 
Additional goals for the H5A interface include keeping storage requirement 
for each attribute to a minimum and easily sharing attributes among 
datasets. 
<p>
Because attributes are intended to be small objects, large datasets 
intended as additional information for a primary dataset should be 
stored as supplemental datasets in a group with the primary dataset. 
Attributes can then be attached to the group containing everything 
to indicate a particular type of dataset with supplemental datasets 
is located in the group. How small is "small" is not defined by the 
library and is up to the user&rsquo;s interpretation. 
<p>
See <a href="../UG/HDF5_Users_Guide-Responsive%20HTML5/index.html#t=HDF5_Users_Guide%2FAttributes%2FHDF5_Attributes.htm">
&ldquo;HDF5 Attributes&rdquo;</a> 
in the <cite>HDF5 User&rsquo;s Guide</cite> for more information.


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