https://svn.boost.org/trac10/ticket/12373 <p> Mature libraries like boost.filesystem shouldn't be giving these sorts of errors with '-Wconversion' checks... </p> <pre class="wiki">/Users/brett/local/include/boost/filesystem/string_file.hpp:27:27: warning: implicit conversion changes signedness: 'size_type' (aka 'unsigned long') to 'streamsize' (aka 'long') [-Wsign-conversion] file.write(str.c_str(), str.size()); ~~~~ ^~~~~~~~~~ /Users/brett/local/include/boost/filesystem/string_file.hpp:38:22: warning: implicit conversion changes signedness: 'std::size_t' (aka 'unsigned long') to 'streamsize' (aka 'long') [-Wsign-conversion] file.read(&amp;str[0], sz); </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/12373 Trac 1.4.3