title: what is msvc_x64_x64 and how is different from msvc_x64
body: <p>I am using visual studio 2019 with cmake project. When opening cmake settings UI in visual studio IDE, it shows a list of toolset for a C++ project.</p>
  
  <p>From the list of toolsets, I have <code>msvc_x64</code> and <code>msvc_x64_x64</code>. I want to build on native x64, so I can simply select msvc_x64.</p>
  
  <p>But why there is two toolset named x64 and x64_x64? </p>
  
  <p>Is it the same thing or they are maintaining two names for some sort of backward compatibility? </p>
  
  <p>As per <a href="https://docs.microsoft.com/en-us/cpp/build/building-on-the-command-line?view=vs-2019" rel="nofollow noreferrer">docs</a>, I can understand the naming conventions for toolsets such as msvc_x86_x64, amd64, x64_arm etc.. I would like to learn about x64 and x64_x64 and why these two exist?</p>
  
  <p>Is there any difference between two ? If so can I get some documentation about it?</p>