https://svn.boost.org/trac10/ticket/12971 <p> The following minimal program "error.cpp" generates the warning: </p> <pre class="wiki">#include &lt;boost/uuid/random_generator.hpp&gt; int main() { boost::uuids::uuid id = boost::uuids::random_generator()(); } </pre><p> Compiling on Windows (MinGW) with </p> <pre class="wiki">g++ -I D:/libraries/boost_1_63_0/ error.cpp </pre><p> yields the following message: </p> <pre class="wiki">In file included from D:/libraries/boost_1_63_0/boost/uuid/random_generator.hpp:12:0, from error.cpp:1: D:/libraries/boost_1_63_0/boost/uuid/seed_rng.hpp: In constructor 'boost::uuids::detail::seed_rng::seed_rng()': D:/libraries/boost_1_63_0/boost/uuid/seed_rng.hpp:96:23: warning: converting to non-pointer type 'boost::detail::winapi::HCRYPTPROV_ {aka long unsigned int}' from NULL [-Wconversion-null] , random_(NULL) ^ D:/libraries/boost_1_63_0/boost/uuid/seed_rng.hpp:106:21: warning: converting to non-pointer type 'boost::detail::winapi::HCRYPTPROV_ {aka long unsigned int}' from NULL [-Wconversion-null] random_ = NULL; ^ </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/12971 Trac 1.4.3 James E. King, III <jking@…> Fri, 04 Aug 2017 01:40:54 GMT https://svn.boost.org/trac10/ticket/12971#comment:2 https://svn.boost.org/trac10/ticket/12971#comment:2 <ul> <li><strong>status</strong> <span class="trac-field-old">new</span> → <span class="trac-field-new">closed</span> </li> <li><strong>resolution</strong> → <span class="trac-field-new">fixed</span> </li> <li><strong>milestone</strong> <span class="trac-field-old">To Be Determined</span> → <span class="trac-field-new">Boost 1.66.0</span> </li> </ul> Ticket