title: Visual Studio how to determine whether a file without a suffix is a C++ header file
body: <p>I've written some header files without suffixes (like .hpp or something) for looks nice.</p>
  <p>But it seems that Visual Studio only reacts to some of these header files, the others are not shown in the include complement and are not automatically highlighted when opened.</p>
  <p>I would like to know how Visual Studio determines that a file without a suffix is a c++ header file in order to hack this mechanism?</p>
  <p><a href="https://i.stack.imgur.com/PxEZU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PxEZU.png" alt="include complement" /></a></p>
  <p><a href="https://i.stack.imgur.com/9l8aC.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9l8aC.png" alt="files" /></a></p>