79 lines
3.8 KiB
HTML
79 lines
3.8 KiB
HTML
<!--$Id: env_class.html 63573 2008-05-23 21:43:21Z trent.nelson $-->
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<!--Copyright (c) 1997,2008 Oracle. All rights reserved.-->
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<!--See the file LICENSE for redistribution information.-->
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<html>
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<head>
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<title>Berkeley DB: db_env_create</title>
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<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
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<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++">
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</head>
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<body bgcolor=white>
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<table width="100%"><tr valign=top>
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<td>
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<b>db_env_create</b>
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</td>
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<td align=right>
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<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a>
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<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td>
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</tr></table>
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<hr size=1 noshade>
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<tt>
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<b><pre>
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#include <db.h>
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<p>
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int
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db_env_create(DB_ENV **dbenvp, u_int32_t flags);
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</pre></b>
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<hr size=1 noshade>
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<b>Description: db_env_create</b>
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<p>The DB_ENV object is the handle for a Berkeley DB environment -- a
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collection including support for some or all of caching, locking,
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logging and transaction subsystems, as well as databases and log files.
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Methods of the DB_ENV handle are used to configure the
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environment as well as to operate on subsystems and databases in the
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environment.</p>
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<p>DB_ENV handles are free-threaded if the <a href="../api_c/env_open.html#DB_THREAD">DB_THREAD</a> flag
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is specified to the <a href="../api_c/env_open.html">DB_ENV->open</a> method when the environment is opened.
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The DB_ENV handle should not be closed while any other handle
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remains open that is using it as a reference (for example, <a href="../api_c/db_class.html">DB</a>
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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
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<a href="../api_c/env_remove.html">DB_ENV->remove</a> methods are called, the handle may not be accessed again,
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regardless of the method's return.</p>
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<p>The db_env_create function creates a DB_ENV structure that
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is the handle for a Berkeley DB environment. This function allocates memory
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for the structure, returning a pointer to the structure in the memory
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to which <b>dbenvp</b> refers. To release the allocated memory and
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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>
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<p>The DB_ENV handle contains a special field, "app_private", which
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is declared as type "void *". This field is provided for the use of
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the application program. It is initialized to NULL and is not further
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used by Berkeley DB in any way.</p>
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<p>The db_env_create method
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returns a non-zero error value on failure
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and 0 on success.
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</p>
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The <b>flags</b> parameter must be set to 0 or
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the following value:
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<br>
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<b><a name="DB_RPCCLIENT">DB_RPCCLIENT</a></b><ul compact><li>Create a client environment to connect to a server.</ul>
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<p>The DB_RPCCLIENT flag indicates to the system that this environment
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is remote on a server. The use of this flag causes the environment
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methods to use functions that call a server instead of local functions.
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Prior to making any environment or database method calls, the application
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must call the <a href="../api_c/env_set_rpc_server.html">DB_ENV->set_rpc_server</a> function to establish the
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connection to the server.</p>
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<br>
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<br><b>Errors</b>
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<hr size=1 noshade>
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<br><b>Class</b>
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DB_ENV
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<br><b>See Also</b>
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<a href="../api_c/env_list.html">Database Environments and Related Methods</a>
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</tt>
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<table width="100%"><tr><td><br></td><td align=right>
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<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>
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</td></tr></table>
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<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font>
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</body>
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</html>
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