将 boost 与 Visual Studio 和 vcpkg 链接时出错答案

【问题标题】：Error linking boost with Visual Studio and vcpkg将 boost 与 Visual Studio 和 vcpkg 链接时出错
【发布时间】：2018-12-01 16:22:29
【问题描述】：

我正在尝试完成一项简单的任务，以检查在 Windows 中开发“Linux 应用程序”是否容易。

我正在使用 Microsoft 的 vcpkg 来设置标头和库以及 crow，这是一个使用 boost 作为驱动程序项目的 c++ http 服务器

来源很简单

#include "crow.hpp"

int main()
{
    crow::SimpleApp app;

    CROW_ROUTE(app, "/")
        ([]() {
        return "Hello world!";
    });

    app.port(18080).run();
}

我已经通过 vcpkg 下载了 boost 并使用 Visual Studio 对项目进行了编码

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"
        }
      ]
    }
  ]
}

链接出错：

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

它会给任何人敲响警钟吗？我为此苦苦挣扎了好几个小时。

【问题讨论】：

您是否尝试过更改您的 cmake 文件以完全匹配 github.com/Microsoft/vcpkg/blob/master/ports/boost/usage？例如在find_package 中，包名应该是Boost 而不是boost，如果找不到boost，添加REQUIRED 会失败（这可能是你的问题？cmake 没有找到boost 并默默地忽略它）跨度>
@AlanBirtles 您的评论足以解决我的问题。如果您有兴趣获得赏金，请回答问题

标签： c++ visual-studio c++11 boost vcpkg

【解决方案1】：

您应该更改您的 cmake 文件以完全匹配 https://github.com/Microsoft/vcpkg/blob/master/ports/boost/usage。

例如在 find_package 中，包名应该是 Boost 而不是 boost，如果找不到 boost，则添加 REQUIRED 会导致失败，cmake 可能找不到 boost 并默默地忽略它。

【讨论】：