<html> <head><title> HDF5/H5 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> <br> <a href="H5.user.html">HDF5 User Guide</a> <br> <a href="index.html">Other HDF5 documents and links</a> <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> <br> 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> <a href="RM_H5I.html">H5I</a> <br> <a href="RM_H5P.html">H5P</a> <a href="RM_H5R.html">H5R</a> <a href="RM_H5RA.html">H5RA</a> <a href="RM_H5S.html">H5S</a> <a href="RM_H5T.html">H5T</a> <a href="RM_H5Z.html">H5Z</a> <a href="Tools.html">Tools</a> </td></tr> </table> </center> <hr> <center> <h1>H5: General Library Functions</h1> </center> These functions serve general-purpose needs of the HDF5 library and it users. <table border=0> <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-DontAtExit">H5dont_atexit</a> </ul> </td></tr> </table> <hr> <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-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> <hr> <center> <table border=0 width=98%> <tr><td valign=top align=left> <a href="H5.intro.html">Introduction to HDF5</a> <br> <a href="H5.user.html">HDF5 User Guide</a> <br> <a href="index.html">Other HDF5 documents and links</a> <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> <br> 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> <a href="RM_H5I.html">H5I</a> <br> <a href="RM_H5P.html">H5P</a> <a href="RM_H5R.html">H5R</a> <a href="RM_H5RA.html">H5RA</a> <a href="RM_H5S.html">H5S</a> <a href="RM_H5T.html">H5T</a> <a href="RM_H5Z.html">H5Z</a> <a href="Tools.html">Tools</a> </td></tr> </table> </center> <hr> <address> <a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a> <br> Last modified: 30 October 1998 </body> </html>