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<h1>DbEnv::lock_get</h1>
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<h3><pre>
#include &lt;db_cxx.h&gt;
<p>
int
DbEnv::lock_get(u_int32_t locker, u_int32_t flags,
    const Dbt *obj, const db_lockmode_t lock_mode, DbLock *lock);
</pre></h3>
<h1>Description</h1>
<p>The DbEnv::lock_get method acquires a lock from the lock table, returning
information about it in
the <b>lock</b> argument.
<p>The <b>locker</b> argument specified to DbEnv::lock_get is an unsigned
32-bit integer quantity.  It represents the entity requesting or releasing
the lock.
<p>The <b>flags</b> value must be set to 0 or the following value:
<p><dl compact>
<p><dt><a name="DB_LOCK_NOWAIT">DB_LOCK_NOWAIT</a><dd>If a lock cannot be granted because the requested lock conflicts with an
existing lock, return immediately instead of waiting for the lock to
become available.
</dl>
<p>The <b>obj</b> argument is an untyped byte string that specifies the
object to be locked or released.
<p>The <b>mode</b> argument is an index into the environment's lock conflict
array.  See <a href="../api_cxx/env_set_lk_conflicts.html">DbEnv::set_lk_conflicts</a> and
<a href="../ref/lock/stdmode.html">Standard Lock Modes</a>
for a description of that array.
<p>The DbEnv::lock_get method may
return or throw an exception encapsulating
one of the following values:
<p><dl compact>
<p><dt><a name="DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a><dd>A lock was requested that could not be immediately granted and the
<b>flags</b> parameter was set to DB_LOCK_NOWAIT.
</dl>
<p>Otherwise, the DbEnv::lock_get method either returns a non-zero error value or throws an exception that
encapsulates a non-zero error value on failure, and returns 0 on success.
<h1>Errors</h1>
<p>The DbEnv::lock_get method may fail and throw an exception or return a non-zero error for the following conditions:
<p><dl compact>
<p><dt>DB_LOCK_DEADLOCK<dd>The operation was selected to resolve a deadlock.
</dl>
<p><dl compact>
<p><dt>EINVAL<dd>An invalid flag value or parameter was specified.
</dl>
<p><dl compact>
<p><dt>ENOMEM<dd>The maximum number of locks has been reached.
</dl>
<p>The DbEnv::lock_get method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods.
If a catastrophic error has occurred, the DbEnv::lock_get method may fail and either
return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a> or throw an exception encapsulating
<a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>, in which case all subsequent Berkeley DB calls will fail
in the same way.
<h3>Classes</h3>
<a href="../api_cxx/dbenv_class.html">DbEnv</a>, <a href="../api_cxx/lock_class.html">DbLock</a>
<h1>See Also</h1>
<a href="../api_cxx/env_set_lk_conflicts.html">DbEnv::set_lk_conflicts</a>,
<a href="../api_cxx/env_set_lk_detect.html">DbEnv::set_lk_detect</a>,
<a href="../api_cxx/env_set_lk_max_locks.html">DbEnv::set_lk_max_locks</a>,
<a href="../api_cxx/env_set_lk_max_lockers.html">DbEnv::set_lk_max_lockers</a>,
<a href="../api_cxx/env_set_lk_max_objects.html">DbEnv::set_lk_max_objects</a>,
<a href="../api_cxx/env_set_lk_max.html">DbEnv::set_lk_max</a>,
<a href="../api_cxx/lock_detect.html">DbEnv::lock_detect</a>,
<a href="../api_cxx/lock_get.html">DbEnv::lock_get</a>,
<a href="../api_cxx/lock_id.html">DbEnv::lock_id</a>,
<a href="../api_cxx/lock_put.html">DbLock::put</a>,
<a href="../api_cxx/lock_stat.html">DbEnv::lock_stat</a>
and
<a href="../api_cxx/lock_vec.html">DbEnv::lock_vec</a>.
</tt>
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