title: CMake include Boost Beast (header only)
body: <p>I want to include <a href="https://github.com/boostorg/beast" rel="nofollow noreferrer">Boost Beast</a> into my project. It's a header-only library. I have cloned the Beast repository into the same directory as my project.</p>
  
  <p>I am using the following in CMake to include the header:</p>
  
  <pre><code>set(BEAST_INCLUDE_DIR ../beast/include)
  
  include_directories(${BEAST_INCLUDE_DIR})
  
  set(SOURCE_FILES ${BEAST_INCLUDE_DIR}/boost/beast.hpp ...)
  
  add_library(my_lib ${SOURCE_FILES})
  </code></pre>
  
  <p>I'm including using the following (alongside other Boost includes):</p>
  
  <pre><code>#include &lt;boost/beast.hpp&gt;
  #include &lt;boost/asio/io_service.hpp&gt;
  </code></pre>
  
  <p>But I get the following error:</p>
  
  <blockquote>
    <p>fatal error: boost/beast.hpp: No such file or directory</p>
  </blockquote>
  
  <p>Do I need to do something special to include another "boost" directory?
  The path of the header is:</p>
  
  <pre><code>beast/include/boost/beast.hpp
  </code></pre>