what is c++ modules and how do they differ from namespaces?
<p>I was looking at libstdc++ documentation at <a href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01618.html" rel="nofollow">http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01618.html</a> and found it arranged in "modules" such as Algorithm, Strings etc</p>

<p>I have multiple questions</p>

<ol>
<li><p>Since this is auto-generated documentation from doxygen, which part of libstdc++ source code or config file, makes doxygen "aware" of different modules and their contents/dependencies?</p></li>
<li><p>What is modules and how does it differ from namespace. </p></li>
<li><p>I did a google search on c++ modules and found that modules are defined by "export modulename", but i could not find any export definition in libstdc++ source code. Does the word "Modules" in the above documentation refer to some different construct than export ?</p></li>
<li><p>Do developers typically divide their source code into modules for large projects?</p></li>
<li><p>where can i learn about modules, so that i can organize my source code into modules and namespaces</p></li>
</ol>
