1<!--$Id: set_func_ioinfo.so,v 10.17 2004/08/13 03:39:02 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB: db_env_set_func_ioinfo</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td> 13<b>db_env_set_func_ioinfo</b> 14</td> 15<td align=right> 16<a href="/api_c/api_core.html"><img src="/images/api.gif" alt="API"></a> 17<a href="/ref/toc.html"><img src="/images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db.h> 23<p> 24int 25db_env_set_func_ioinfo(int (*func_ioinfo)(const char *path, 26 int fd, u_int32_t *mbytesp, u_int32_t *bytesp, u_int32_t *iosizep)); 27</pre></b> 28<hr size=1 noshade> 29<b>Description: db_env_set_func_ioinfo</b> 30<p>The Berkeley DB library requires the ability to determine the size and I/O 31characteristics of a file.</p> 32<p>The db_env_set_func_ioinfo method configures all operations performed by a process and 33all of its threads of control, not operations confined to a single 34database environment.</p> 35<p>Although the db_env_set_func_ioinfo method may be called at any time during the life of 36the application, it should normally be called before making calls to the 37<a href="/api_c/env_class.html">db_env_create</a> or <a href="/api_c/db_class.html">db_create</a> methods.</p> 38<p>The db_env_set_func_ioinfo method 39returns a non-zero error value on failure 40and 0 on success. 41</p> 42<b>Parameters</b> <br> 43 <b>func_ioinfo</b><ul compact><li>The <b>func_ioinfo</b> parameter is the function which returns the size 44and I/O characteristics of a file. 45<p>The <b>path</b> parameter is the pathname of the file to be checked, and the 46<b>fd</b> parameter is an open file descriptor on the file.</p> 47<p>If the <b>mbytesp</b> and <b>bytesp</b> parameters are non-NULL, the 48<b>ioinfo</b> function must return in them the size of the file: the 49number of megabytes in the file into the memory location to which the 50<b>mbytesp</b> parameter refers, and the number of bytes over and above 51that number of megabytes into the memory location to which the 52<b>bytesp</b> parameter refers.</p> 53<p>In addition, if the <b>iosizep</b> parameter is non-NULL, the <b>ioinfo</b> 54function must return the optimum granularity for I/O operations to the file 55into the memory location to which it refers.</p> 56<p>The <b>func_ioinfo</b> function must return the value of <b>errno</b> on 57failure and 0 on success.</p></ul> 58<br> 59<br><b>See Also</b> 60<a href="/ref/program/runtime.html">Run-time configuration</a> 61</tt> 62<table width="100%"><tr><td><br></td><td align=right> 63<a href="/api_c/api_core.html"><img src="/images/api.gif" alt="API"></a><a href="/ref/toc.html"><img src="/images/ref.gif" alt="Ref"></a> 64</td></tr></table> 65<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 66</body> 67</html> 68