1<!--$Id: set_func_file_map.so,v 10.22 2008/01/17 03:26:52 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_file_map</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_file_map</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_file_map(int (*func_file_map)(DB_ENV *dbenv, char *path, size_t len, int is_rdonly, void **addr), 26 int (*func_file_unmap)(DB_ENV *dbenv, void *addr)); 27</pre></b> 28<hr size=1 noshade> 29<b>Description: db_env_set_func_file_map</b> 30<p>The Berkeley DB library optionally uses the ability to map a file into memory.</p> 31<p>The db_env_set_func_file_map method configures all operations performed by a process and 32all of its threads of control, not operations confined to a single 33database environment.</p> 34<p>Although the db_env_set_func_file_map method may be called at any time during the life of 35the application, it should normally be called before making calls to the 36<a href="../api_c/env_class.html">db_env_create</a> or <a href="../api_c/db_class.html">db_create</a> methods.</p> 37<p>The db_env_set_func_file_map method 38returns a non-zero error value on failure 39and 0 on success. 40</p> 41<b>Parameters</b> <br> 42 <b>func_file_map</b><ul compact><li>The <b>func_file_map</b> parameter is the function which maps a file 43into memory. The function takes 5 parameters: 44<br> 45<b><b>dbenv</b></b><ul compact><li>The <b>dbenv</b> parameter is the enclosing database environment handle.</ul> 46<b><b>path</b></b><ul compact><li>The <b>path</b> parameter is the name of file. Repeated requests for 47the mapping of the same name should return a reference to the same 48memory.</ul> 49<b><b>len</b></b><ul compact><li>The <b>len</b> parameter is the length, in bytes, of the file.</ul> 50<b><b>is_rdonly</b></b><ul compact><li>The <b>is_rdonly</b> parameter will be non-zero if the mapped file is 51read-only.</ul> 52<b><b>addr</b></b><ul compact><li>The <b>addr</b> parameter is the memory location into which a pointer 53to the mapped file is returned.</ul> 54<br> 55<p>The <b>func_file_map</b> function must return the value of <b>errno</b> on 56failure and 0 on success.</p></ul> 57 <b>func_file_unmap</b><ul compact><li>The <b>func_file_unmap</b> parameter is the function which unmaps a 58file from memory. The function takes 2 parameters: 59<br> 60<b><b>dbenv</b></b><ul compact><li>The <b>dbenv</b> parameter is the enclosing database environment handle.</ul> 61<b><b>addr</b></b><ul compact><li>The <b>addr</b> parameter is the value returned by the 62<b>func_file_map</b> function when the file or region was mapped into 63memory.</ul> 64<br> 65<p>The <b>func_file_unmap</b> function must return the value of <b>errno</b> on 66failure and 0 on success.</p></ul> 67<br> 68<br><b>See Also</b> 69<a href="../ref/program/runtime.html">Run-time configuration</a> 70</tt> 71<table width="100%"><tr><td><br></td><td align=right> 72<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> 73</td></tr></table> 74<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 75</body> 76</html> 77