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6<title>Berkeley DB: DbEnv::mutex_lock</title>
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13<b>DbEnv::mutex_lock</b>
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21<b><pre>
22#include &lt;db_cxx.h&gt;
23<p>
24int
25DbEnv::mutex_lock(db_mutex_t mutex);
26</pre></b>
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28<b>Description: DbEnv::mutex_lock</b>
29<p>The DbEnv::mutex_lock method locks the mutex allocated by
30<a href="/api_cxx/mutex_alloc.html">DbEnv::mutex_alloc</a>.  The thread of control calling DbEnv::mutex_lock
31will block until the lock is available.</p>
32<p>The DbEnv::mutex_lock method may not be called before the <a href="/api_cxx/env_open.html">DbEnv::open</a> method is called.</p>
33<p>The DbEnv::mutex_lock method
34either returns a non-zero error value
35or throws an exception that encapsulates a non-zero error value on
36failure, and returns 0 on success.
37</p>
38<b>Parameters</b> <br>
39 <b>mutex</b><ul compact><li>The <b>mutex</b> parameter is a mutex previously allocated by
40<a href="/api_cxx/mutex_alloc.html">DbEnv::mutex_alloc</a>.</ul>
41<br>
42<br><b>Errors</b>
43<p>The DbEnv::mutex_lock method
44may fail and throw
45<a href="/api_cxx/except_class.html">DbException</a>,
46encapsulating one of the following non-zero errors, or return one of
47the following non-zero errors:</p>
48<br>
49<b>EINVAL</b><ul compact><li>An
50invalid flag value or parameter was specified.</ul>
51<br>
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53<br><b>Class</b>
54<a href="/api_cxx/env_class.html">DbEnv</a>
55<br><b>See Also</b>
56<a href="/api_cxx/env_list.html">Database Environments and Related Methods</a>
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