1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>Error Returns</title> 7 <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.62.4" /> 9 <link rel="home" href="index.html" title="Getting Started with Berkeley DB" /> 10 <link rel="up" href="introduction.html" title="Chapter��1.��Introduction to Berkeley DB " /> 11 <link rel="previous" href="coreExceptions.html" title="Exception Handling" /> 12 <link rel="next" href="gettingit.html" title="Getting and Using DB " /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">Error Returns</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="coreExceptions.html">Prev</a>��</td> 22 <th width="60%" align="center">Chapter��1.��Introduction to Berkeley DB </th> 23 <td width="20%" align="right">��<a accesskey="n" href="gettingit.html">Next</a></td> 24 </tr> 25 </table> 26 <hr /> 27 </div> 28 <div class="sect1" lang="en" xml:lang="en"> 29 <div class="titlepage"> 30 <div> 31 <div> 32 <h2 class="title" style="clear: both"><a id="returns"></a>Error Returns</h2> 33 </div> 34 </div> 35 <div></div> 36 </div> 37 <p> 38 <span>In addition to exceptions, the</span> 39 40 DB interfaces always return a value of 0 on success. If the 41 operation does not succeed for any reason, the return value will be 42 non-zero. 43 </p> 44 <p> 45 If a system error occurred (for example, DB ran out of disk 46 space, or permission to access a file was denied, or an illegal argument 47 was specified to one of the interfaces), DB returns an 48 <tt class="literal">errno</tt> 49 value. All of the possible values of <tt class="literal">errno</tt> are greater than 0. 50 </p> 51 <p> 52 If the operation did not fail due to a system error, but was not 53 successful either, DB returns a special error value. For 54 example, if you tried to retrieve data from the database and the 55 record for which you are searching does not exist, DB would return 56 <tt class="literal">DB_NOTFOUND</tt>, a special error value that means the requested 57 key does not appear in the database. All of the possible special error 58 values are less than 0. 59 </p> 60 </div> 61 <div class="navfooter"> 62 <hr /> 63 <table width="100%" summary="Navigation footer"> 64 <tr> 65 <td width="40%" align="left"><a accesskey="p" href="coreExceptions.html">Prev</a>��</td> 66 <td width="20%" align="center"> 67 <a accesskey="u" href="introduction.html">Up</a> 68 </td> 69 <td width="40%" align="right">��<a accesskey="n" href="gettingit.html">Next</a></td> 70 </tr> 71 <tr> 72 <td width="40%" align="left" valign="top">Exception Handling��</td> 73 <td width="20%" align="center"> 74 <a accesskey="h" href="index.html">Home</a> 75 </td> 76 <td width="40%" align="right" valign="top">��Getting and Using DB </td> 77 </tr> 78 </table> 79 </div> 80 </body> 81</html> 82