</span>BOOST_LOG_ONCE_BLOCK_FLAG(flag_var)</pre></div>
<div class="refsect1">
-<a name="idm46436892244448"></a><h2>Description</h2>
+<a name="idm45554723739648"></a><h2>Description</h2>
<p>Begins a code block to be executed only once, with protection against thread concurrency. User has to provide the flag variable that controls whether the block has already been executed. </p>
</div>
</div>