https://svn.boost.org/trac10/ticket/12333 <p> … which is not surprise: </p> <pre class="wiki"> template &lt;typename T&gt; unsigned char hex_char_to_int ( T val ) { char c = static_cast&lt;char&gt; ( val ); unsigned retval = 0; // &lt;-- // ... return retval; // &lt;-- } </pre><p> Compiler output: </p> <pre class="wiki">1&gt;boost/algorithm/hex.hpp(74): warning C4244: 'return': conversion from 'unsigned int' to 'unsigned char', possible loss of data 1&gt; boost/algorithm/hex.hpp(129): note: see reference to function template instantiation 'unsigned char boost::algorithm::detail::hex_char_to_int&lt;char&gt;(T)' being compiled 1&gt; with 1&gt; [ 1&gt; T=char 1&gt; ] 1&gt; boost/algorithm/hex.hpp(196): note: see reference to function template instantiation 'unsigned char *boost::algorithm::detail::decode_one&lt;InputIterator,OutputIterator,bool(__cdecl *)(Iterator,Iterator)&gt;(InputIterator &amp;,InputIterator,OutputIterator,EndPred)' being compiled 1&gt; with 1&gt; [ 1&gt; InputIterator=const char *, 1&gt; OutputIterator=unsigned char *, 1&gt; Iterator=const char *, 1&gt; EndPred=bool (__cdecl *)(const char *,const char *) 1&gt; ] </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/12333 Trac 1.4.3 Marshall Clow Mon, 18 Jul 2016 18:36:52 GMT https://svn.boost.org/trac10/ticket/12333#comment:1 https://svn.boost.org/trac10/ticket/12333#comment:1 <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">invalid</span> </li> </ul> <p> We've been down this road before; the compiler is flat out wrong here. </p> <p> This function returns a value in the range 0 .. 255; there is no loss of data. </p> <p> Please report this bug against the MS compiler instead. </p> Ticket pravic <ehysta@…> Mon, 18 Jul 2016 19:23:53 GMT