Error linking boost with Visual Studio and vcpkg - c++

Question

I am trying to accomplish a simple task in order to check how easy is to develop "Linux apps" in Windows.
I am using vcpkg from Microsoft in order to setup headers and libs and crow , an c++ http server that uses boost as a driver project
The source is simple
#include "crow.hpp"
int main()
{
crow::SimpleApp app;
CROW_ROUTE(app, "/")
([]() {
return "Hello world!";
});
app.port(18080).run();
}
I have downloaded boost via vcpkg and used Visual Studio to code the project
cmake:
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 ${Boost_LIBRARIES})
CMakeSettings.json
{
"configurations": [
{
"name": "x86-Debug",
"generator": "Visual Studio 15 2017",
"configurationType": "Debug",
"buildRoot": "${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"
}
]
}
]
}
Linking gives errors:
error LNK2019: unresolved external symbol "__declspec(dllimport) class boost::system::error_category const & __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 & __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 &,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<struct boost::date_time::year_month_day_base<class boost::gregorian::greg_year,class boost::gregorian::greg_month,class boost::gregorian::greg_day>,unsigned int>::day_number(struct boost::date_time::year_month_day_base<class boost::gregorian::greg_year,class boost::gregorian::greg_month,class boost::gregorian::greg_day> const &)" (?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
Does it ring a bell to anyone? I am struggling hours with this.

Answer 1

You should change your cmake file to exactly match https://github.com/Microsoft/vcpkg/blob/master/ports/boost/usage.
e.g. in find_package the package name should be Boost not boost, adding REQUIRED would make it fail if boost isn't found, cmake is possibly not finding boost and silently ignoring it.