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</pre> 43 <p> 44 The Berkeley DB library requires the ability to determine the size and 45 I/O characteristics of a file. 46 </p> 47 <p> 48 The <code class="function">db_env_set_func_ioinfo()</code> function configures all operations performed 49 by a process and all of its threads of control, not operations 50 confined to a single database environment. 51 </p> 52 <p> 53 Although the <code class="function">db_env_set_func_ioinfo()</code> function may be called at any time 54 during the life of the application, it should normally be called 55 before making calls to the <a class="xref" href="envcreate.html" title="db_env_create">db_env_create</a> or 56 <a class="xref" href="dbcreate.html" title="db_create">db_create</a> methods. 57 </p> 58 <p> 59 The <code class="function">db_env_set_func_ioinfo()</code> <span> 60 function returns a non-zero error value on failure and 0 on success. 61 </span> 62 </p> 63 <div class="sect2" lang="en" xml:lang="en"> 64 <div class="titlepage"> 65 <div> 66 <div> 67 <h3 class="title"><a id="id1719486"></a>Parameters</h3> 68 </div> 69 </div> 70 </div> 71 <div class="sect3" lang="en" xml:lang="en"> 72 <div class="titlepage"> 73 <div> 74 <div> 75 <h4 class="title"><a id="id1719693"></a>func_ioinfo</h4> 76 </div> 77 </div> 78 </div> 79 <p> 80 The <span class="bold"><strong>func_ioinfo</strong></span> parameter is the 81 function which returns the size and I/O characteristics of a file. 82 </p> 83 <p> 84 The <span class="bold"><strong>path</strong></span> parameter is the pathname of 85 the file to be checked, and the <span class="bold"><strong>fd</strong></span> 86 parameter is an open file descriptor on the file. 87 </p> 88 <p> 89 If the <span class="bold"><strong>mbytesp</strong></span> and <span class="bold"><strong>bytesp</strong></span> parameters are non-NULL, the <span class="bold"><strong>ioinfo</strong></span> function must return in them the size of 90 the file: the number of megabytes in the file into the memory location 91 to which the <span class="bold"><strong>mbytesp</strong></span> parameter 92 refers, and the number of bytes over and above that number of 93 megabytes into the memory location to which the <span class="bold"><strong>bytesp</strong></span> parameter refers. 94 </p> 95 <p> 96 In addition, if the <span class="bold"><strong>iosizep</strong></span> parameter 97 is non-NULL, the <span class="bold"><strong>ioinfo</strong></span> function must 98 return the optimum granularity for I/O operations to the file into the 99 memory location to which it refers. 100 </p> 101 <p> 102 The <span class="bold"><strong>func_ioinfo</strong></span> function must return 103 the value of <span class="bold"><strong>errno</strong></span> on failure and 0 104 on success. 105 </p> 106 </div> 107 </div> 108 <div class="sect2" lang="en" xml:lang="en"> 109 <div class="titlepage"> 110 <div> 111 <div> 112 <h3 class="title"><a id="id1719888"></a>See Also</h3> 113 </div> 114 </div> 115 </div> 116 <p> 117 <a href="../../programmer_reference/program_runtime.html" class="olink">Run-time configuration</a> 118 119 </p> 120 </div> 121 </div> 122 <div class="navfooter"> 123 <hr /> 124 <table width="100%" summary="Navigation footer"> 125 <tr> 126 <td width="40%" align="left"><a accesskey="p" href="db_env_set_func_ftruncate.html">Prev</a>��</td> 127 <td width="20%" align="center"> 128 <a accesskey="u" href="setfunc.html">Up</a> 129 </td> 130 <td width="40%" align="right">��<a accesskey="n" href="db_env_set_func_malloc.html">Next</a></td> 131 </tr> 132 <tr> 133 <td width="40%" align="left" valign="top">db_env_set_func_ftruncate��</td> 134 <td width="20%" align="center"> 135 <a accesskey="h" href="index.html">Home</a> 136 </td> 137 <td width="40%" align="right" valign="top">��db_env_set_func_malloc</td> 138 </tr> 139 </table> 140 </div> 141 </body> 142</html> 143