<!--$Id: env_class.so,v 10.45 2005/11/30 19:09:47 bostic Exp $--> <!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: db_env_create</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <table width="100%"><tr valign=top> <td> <b>db_env_create</b> </td> <td align=right> <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></td> </tr></table> <hr size=1 noshade> <tt> <b><pre> #include <db.h> <p> int db_env_create(DB_ENV **dbenvp, u_int32_t flags); </pre></b> <hr size=1 noshade> <b>Description: db_env_create</b> <p>The DB_ENV object is the handle for a Berkeley DB environment -- a collection including support for some or all of caching, locking, logging and transaction subsystems, as well as databases and log files. Methods of the DB_ENV handle are used to configure the environment as well as to operate on subsystems and databases in the environment.</p> <p>DB_ENV handles are free-threaded if the <a href="../api_c/env_open.html#DB_THREAD">DB_THREAD</a> flag is specified to the <a href="../api_c/env_open.html">DB_ENV->open</a> method when the environment is opened. The DB_ENV handle should not be closed while any other handle remains open that is using it as a reference (for example, <a href="../api_c/db_class.html">DB</a> or <a href="../api_c/txn_class.html">DB_TXN</a>). Once either the <a href="../api_c/env_close.html">DB_ENV->close</a> or <a href="../api_c/env_remove.html">DB_ENV->remove</a> methods are called, the handle may not be accessed again, regardless of the method's return.</p> <p>The db_env_create function creates a DB_ENV structure that is the handle for a Berkeley DB environment. This function allocates memory for the structure, returning a pointer to the structure in the memory to which <b>dbenvp</b> refers. To release the allocated memory and discard the handle, call the <a href="../api_c/env_close.html">DB_ENV->close</a> or <a href="../api_c/env_remove.html">DB_ENV->remove</a> methods.</p> <p>The DB_ENV handle contains a special field, "app_private", which is declared as type "void *". This field is provided for the use of the application program. It is initialized to NULL and is not further used by Berkeley DB in any way.</p> <p>The db_env_create method returns a non-zero error value on failure and 0 on success. </p> The <b>flags</b> parameter must be set to 0 or the following value: <br> <b><a name="DB_RPCCLIENT">DB_RPCCLIENT</a></b><ul compact><li>Create a client environment to connect to a server.</ul> <p>The DB_RPCCLIENT flag indicates to the system that this environment is remote on a server. The use of this flag causes the environment methods to use functions that call a server instead of local functions. Prior to making any environment or database method calls, the application must call the <a href="../api_c/env_set_rpc_server.html">DB_ENV->set_rpc_server</a> function to establish the connection to the server.</p> <br> <br><b>Errors</b> <hr size=1 noshade> <br><b>Class</b> DB_ENV <br><b>See Also</b> <a href="../api_c/env_list.html">Database Environments and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <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> </td></tr></table> <p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> </body> </html>