On Friday, April 13, 2018, Chris Glover wrote:<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><div><br></div><div>There are of course other reasons for choosing the boost variant over the std variant, even outside of boost. Four that often influence me are:</div><div><br></div><div>- Boost often offers an extended API</div><div>- Boost components can be forward declared</div><div>- Boost offers the same implementation across platforms</div><div>- I can fix a boost version should I need to</div><div><br></div><div>My projects tend to reach for boost over std for most components as a result of this.</div><div><br></div><div>-- chris</div></div></div></blockquote><div><br></div><div>Additionally, speaking specifically about boost::shared_ptr here:</div><div><br></div><div>1. Reasons some users choose boost::shared_ptr in C++11 and C++14 code:</div><div>- shared_ptr&lt;T[]&gt;  (C++17 only)</div><div>- local_shared_ptr&lt;T&gt; (Boost only, interoperates with boost::shared_ptr&lt;T&gt;)</div><div><br></div><div>2. Reasons some users choose boost::shared_ptr in C++17 code:</div><div>- make_shared&lt;T[]&gt; and allocate_shared&lt;T[]&gt; (C++20 only)</div><div>- local_shared_ptr&lt;T&gt; (Boost only, interoperates with boost::shared_ptr&lt;T&gt;)<br></div><div><br></div><div>3. Reasons some users choose boost::shared_ptr in C++2a code:</div><div><div>- make_shared&lt;T[]&gt; and allocate_shared&lt;T[]&gt; (until all vendors implement it)</div><div>- local_shared_ptr&lt;T&gt; (Boost only, interoperates with boost::shared_ptr&lt;T&gt;)</div></div><div><br></div><div>Glen</div><div><br></div>