title: Error linking boost with Visual Studio and vcpkg
body: <p>I am trying to accomplish a simple task in order to check how easy is to develop "Linux apps" in Windows.</p>
  
  <p>I am using <a href="https://github.com/Microsoft/vcpkg" rel="noreferrer">vcpkg</a> from Microsoft in order to setup headers and libs and <a href="https://github.com/ipkn/crow" rel="noreferrer">crow</a> , an c++ http server that uses boost as a driver project</p>
  
  <p>The source is simple</p>
  
  <pre><code>#include "crow.hpp"
  
  int main()
  {
      crow::SimpleApp app;
  
      CROW_ROUTE(app, "/")
          ([]() {
          return "Hello world!";
      });
  
      app.port(18080).run();
  }
  </code></pre>
  
  <p>I have downloaded boost via vcpkg and used Visual Studio to code the project</p>
  
  <p>cmake:</p>
  
  <pre><code>cmake_minimum_required (VERSION 3.8)
  find_package(boost COMPONENTS  filesystem system thread date_time REQUIRED)
  message("this is ${Boost_INCLUDE_DIRS}")
  include_directories ("C:\\github.com\\crow\\include")
  include_directories(SYSTEM PUBLIC ${Boost_INCLUDE_DIRS})
  
  add_executable (engine "promo-engine-windows.cpp" "promo-engine-windows.h")
  
  target_link_libraries(engine  ${Boost_LIBRARIES})
  </code></pre>
  
  <p>CMakeSettings.json</p>
  
  <pre><code>{
    "configurations": [
      {
        "name": "x86-Debug",
        "generator": "Visual Studio 15 2017",
        "configurationType": "Debug",
        "buildRoot": "${env.USERPROFILE}\\CMakeBuilds\\${workspaceHash}\\build\\${name}",
        "cmakeCommandArgs": "",
        "buildCommandArgs": "-m -v:minimal",
        "variables": [
          {
            "name": "CMAKE_TOOLCHAIN_FILE",
            "value": "C:\\github.com\\vcpkg\\scripts\\buildsystems\\vcpkg.cmake"
          }
        ]
      }
    ]
  }
  </code></pre>
  
  <p>Linking gives errors:</p>
  
  <pre><code>error LNK2019: unresolved external symbol "__declspec(dllimport) class boost::system::error_category const &amp; __cdecl boost::system::system_category(void)" (__imp_?system_category@system@boost@@YAABVerror_category@12@XZ) referenced in function "public: __thiscall boost::system::error_code::error_code(void)" (??0error_code@system@boost@@QAE@XZ) 
  
  error LNK2019: unresolved external symbol "__declspec(dllimport) class boost::system::error_category const &amp; __cdecl boost::system::generic_category(void)" (__imp_?generic_category@system@boost@@YAABVerror_category@12@XZ) referenced in function "public: virtual bool __thiscall boost::system::error_category::std_category::equivalent(class std::error_code const &amp;,int)const " (?equivalent@std_category@error_category@system@boost@@UBE_NABVerror_code@std@@H@Z) 
  
  error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall boost::gregorian::greg_month::greg_month(unsigned short)" (__imp_??0greg_month@gregorian@boost@@QAE@G@Z) referenced in function "public: __thiscall boost::gregorian::date::date(enum boost::date_time::special_values)" (??0date@gregorian@boost@@QAE@W4special_values@date_time@2@@Z) 
  
  error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall boost::gregorian::greg_month::operator unsigned short(void)const " (__imp_??Bgreg_month@gregorian@boost@@QBEGXZ) referenced in function "public: static unsigned int __cdecl boost::date_time::gregorian_calendar_base&lt;struct boost::date_time::year_month_day_base&lt;class boost::gregorian::greg_year,class boost::gregorian::greg_month,class boost::gregorian::greg_day&gt;,unsigned int&gt;::day_number(struct boost::date_time::year_month_day_base&lt;class boost::gregorian::greg_year,class boost::gregorian::greg_month,class boost::gregorian::greg_day&gt; const &amp;)" (?day_number@?$gregorian_calendar_base@U?$year_month_day_base@Vgreg_year@gregorian@boost@@Vgreg_month@23@Vgreg_day@23@@date_time@boost@@I@date_time@boost@@SAIABU?$year_month_day_base@Vgreg_year@gregorian@boost@@Vgreg_month@23@Vgreg_day@23@@23@@Z) 
  
  fatal error LNK1120: 4 unresolved externals 
  
  Build failed
  </code></pre>
  
  <p>Does it ring a bell to anyone? I am struggling hours with this. </p>