The obvious one would be #include &lt;windows.h&gt;.  I have never checked to see how big that file actually is, but it&#x27;s not anywhere near what you would think based on what functions MSDN says need you to #include it for. The truth is, it #includes several other files, because Microsoft, in its infinite wisdom decided that, for the most part, programmers don&#x27;t have to know what file a declaration is actually in, they just need to remember #include &lt;windows.h&gt;.