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HDF5/H5 API Specification
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And in this document, the
<a href="RM_H5Front.html">HDF5 Reference Manual</a>
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H5
<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>
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<h1>H5: General Library Functions</h1>
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These functions serve general-purpose needs of the HDF5 library
and it users.
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<tr><td valign=top>
<ul>
<li><a href="#Library-Open">H5open</a>
<li><a href="#Library-Close">H5close</a>
</ul>
</td><td> </td><td valign=top>
<ul>
<li><a href="#Library-Version">H5get_libversion</a>
<li><a href="#Library-VersCheck">H5check_version</a>
</ul>
</td><td> </td><td valign=top>
<ul>
<li><a href="#Library-GarbageCollect">H5garbage_collect</a>
<li><a href="#Library-DontAtExit">H5dont_atexit</a>
</ul>
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</table>
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<dl>
<dt><strong>Name:</strong> <a name="Library-Open">H5open</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5open</code>(<em>void</em>)
<dt><strong>Purpose:</strong>
<dd>Initializes the HDF5 library.
<dt><strong>Description:</strong>
<dd><code>H5open</code> initialize the library. This function is
normally called automatically, but if you find that an
HDF5 library function is failing inexplicably, try calling
this function first.
<dt><strong>Parameters:</strong>
<dl>
<dt>None.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
</dl>
<hr>
<dl>
<dt><strong>Name:</strong> <a name="Library-Close">H5close</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5close</code>(<em>void</em>)
<dt><strong>Purpose:</strong>
<dd>Flushes all data to disk, closes file identifiers, and cleans up memory.
<dt><strong>Description:</strong>
<dd><code>H5close</code> flushes all data to disk,
closes all file identifiers, and cleans up all memory used by
the library. This function is generall called when the
application calls <code>exit</code>, but may be called earlier
in event of an emergency shutdown or out of desire to free all
resources used by the HDF5 library.
<dt><strong>Parameters:</strong>
<dl>
<dt>None.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
</dl>
<hr>
<dl>
<dt><strong>Name:</strong> <a name="Library-GarbageCollect">H5garbage_collect</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5garbage_collect</code>(<em>void</em>)
<dt><strong>Purpose:</strong>
<dd>Garbage collects on all free-lists of all types.
<dt><strong>Description:</strong>
<dd><code>H5garbage_collect</code> walks through all the garbage
collection routines of the library, freeing any unused memory.
<p>
It is not required that <code>H5garbage_collect</code> be called
at any particular time; it is only necessary in certain situations
where the application has performed actions that cause the library
to allocate many objects. The application should call
<code>H5garbage_collect</code> if it eventually releases those
objects and wants to reduce the memory used by the library from
the peak usage required.
<p>
The library automatically garbage collects all the free lists
when the application ends.
<dt><strong>Parameters:</strong>
<dl>
<dt>None.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
</dl>
<hr>
<dl>
<dt><strong>Name:</strong> <a name="Library-DontAtExit">H5dont_atexit</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5dont_atexit</code>(<em>void</em>)
<dt><strong>Purpose:</strong>
<dd>Instructs library not to install <code>atexit</code> cleanup routine.
<dt><strong>Description:</strong>
<dd><code>H5dont_atexit</code> indicates to the library that an
<code>atexit()</code> cleanup routine should not be installed.
The major purpose for this is in situations where the
library is dynamically linked into an application and is
un-linked from the application before <code>exit()</code> gets
called. In those situations, a routine installed with
<code>atexit()</code> would jump to a routine which was
no longer in memory, causing errors.
<p>
In order to be effective, this routine <em>must</em> be called
before any other HDF function calls, and must be called each
time the library is loaded/linked into the application
(the first time and after it's been un-loaded).
<dt><strong>Parameters:</strong>
<dl>
<dt>None.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
</dl>
<hr>
<dl>
<dt><strong>Name:</strong> <a name="Library-Version">H5get_libversion</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5get_libversion</code>(<em>unsigned *</em><code>majnum</code>,
<em>unsigned *</em><code>minnum</code>,
<em>unsigned *</em><code>relnum</code>
)
<dt><strong>Purpose:</strong>
<dd>Returns the HDF library release number.
<dt><strong>Description:</strong>
<dd><code>H5get_libversion</code> retrieves the major, minor, and release
numbers of the version of the HDF library which is linked to
the application.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>unsigned *</em><code>majnum</code>
<dd>OUT: The major version of the library.
<dt><em>unsigned *</em><code>minnum</code>
<dd>OUT: The minor version of the library.
<dt><em>unsigned *</em><code>relnum</code>
<dd>OUT: The release number of the library.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful;
otherwise returns a negative value.
</dl>
<hr>
<dl>
<dt><strong>Name:</strong> <a name="Library-VersCheck">H5check_version</a>
<dt><strong>Signature:</strong>
<dd><em>herr_t</em> <code>H5check_version</code>(<em>unsigned</em> <code>majnum</code>,
<em>unsigned</em> <code>minnum</code>,
<em>unsigned</em> <code>relnum</code>
)
<dt><strong>Purpose:</strong>
<dd>
<dt><strong>Description:</strong>
<dd><code>H5check_version</code> verifies that the arguments match the
version numbers compiled into the library. This function is intended
to be called by the user to verify that the version of the header files
compiled into the application matches the version of the HDF5 library
being used.
<p>
Due to the risks of data corruption or segmentation faults,
<code>H5check_version</code> causes the application to abort if the
version numbers do not match.
<p>
If the version numbers of the library do not match
the version numbers in the header files being checked, the library calls the
standard C function <code>abort()</code>.
<dt><strong>Parameters:</strong>
<dl>
<dt><em>unsigned </em><code>majnum</code>
<dd>IN: The major version of the library.
<dt><em>unsigned </em><code>minnum</code>
<dd>IN: The minor version of the library.
<dt><em>unsigned </em><code>relnum</code>
<dd>IN: The release number of the library.
</dl>
<dt><strong>Returns:</strong>
<dd>Returns a non-negative value if successful.
Upon failure, this function causes the application to abort.
</dl>
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And in this document, the
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Last modified: 17 July 2000
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Describes HDF5 Release 1.4 Beta, December 2000
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