ss="identifier">set_checkpoint</span><span class="special">(</span><span class="identifier">const_string</span> file<span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> line_num<span class="special">,</span> 
                    <span class="identifier">const_string</span> msg <span class="special">=</span> <span class="identifier">const_string</span><span class="special">(</span><span class="special">)</span><span class="spe