问题描述
我正在遵循https://badprog.com/c-boost-setting-up-on-windows-10的指示。我已安装Visual Studio 2017，并安装了boost_1_71_0-msvc-14.1-64.exe。 CMake已从cmake.org/download/，cmake-3.19.0-rc1-win64-x64.msi下载。
我有一个需要Boost Beast的项目，我认为它是1.70或更高版本。
我运行cmake .时一切正常：
C:\Users\Public\xyz>cmake .
-- Building for: Visual Studio 16 2019
-- Selecting Windows SDK version 10.0.17763.0 to target Windows 10.0.18362.
-- The CXX compiler identification is MSVC 19.24.28314.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.24.28314/bin/Hostx64/x64/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Looking for C++ include pthread.h
-- Looking for C++ include pthread.h - not found
-- Found Threads: TRUE
-- Found Boost: C:/local/boost_1_71_0 (found suitable version "1.71.0",minimum required is "1.70") found components: thread system chrono date_time atomic
-- Configuring done
-- Generating done
-- Build files have been written to: C:/Users/Public/xyz
生成的项目在Visual Studio 2017中打开，但随后抱怨它需要2019生成工具。令人惊讶的是，正如您在上面看到的那样，它是为Visual Studio 2019构建的吗？
但是，在杀死CMakeCache.txt和CMakeFiles之后，如果我这样做：
C:\Users\Public\xyz>cmake -G "Visual Studio 15 2017" .
-- Selecting Windows SDK version 10.0.17763.0 to target Windows 10.0.18362.
-- The CXX compiler identification is MSVC 19.16.27034.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x86/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Looking for C++ include pthread.h
-- Looking for C++ include pthread.h - not found
-- Found Threads: TRUE
CMake Error at C:/Program Files/CMake/share/cmake-3.19/Modules/FindPackageHandleStandardArgs.cmake:218 (message):
Could NOT find Boost (missing: thread system) (found suitable version
"1.71.0",minimum required is "1.70")
Call Stack (most recent call first):
C:/Program Files/CMake/share/cmake-3.19/Modules/FindPackageHandleStandardArgs.cmake:577 (_FPHSA_FAILURE_MESSAGE)
C:/Program Files/CMake/share/cmake-3.19/Modules/FindBoost.cmake:2176 (find_package_handle_standard_args)
CMakeLists.txt:29 (FIND_PACKAGE)
-- Configuring incomplete,errors occurred!
See also "C:/Users/Public/xyz/CMakeFiles/CMakeOutput.log".
突然找不到Boost组件（但可以找到Boost吗？）。我尝试了各种形式的-DBOOST_LIBRARYDIR或-DBOOST_ROOT等，但都无济于事，但是我似乎没有cmake无法找到Boost的通常的stackoverflow问题。相反，尽管已为msvc-14.1安装了它，但似乎无法识别Visual Studio 2017目标？
CMakeLists.txt：
# Specify the minimum version for CMake
cmake_minimum_required(VERSION 3.1)
# Force C++11,for Boost Beast (async http library)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_required ON)
set(CMAKE_CXX_EXTENSIONS OFF)
# Project's name
project(xyz
VERSION 0.1
LANGUAGES CXX)
# Set the output folder where the program will be created
set(CMAKE_BINARY_DIR ${CMAKE_SOURCE_DIR}/build)
set(EXECUTABLE_OUTPUT_PATH ${CMAKE_BINARY_DIR})
set(LIBRARY_OUTPUT_PATH ${CMAKE_BINARY_DIR})
# Specify .cpp and .hpp is in src/
set(PROJECT_SOURCE_DIR ${CMAKE_SOURCE_DIR}/src)
include_directories("${PROJECT_SOURCE_DIR}")
# Add source to build target for hello world...
add_executable(main ${PROJECT_SOURCE_DIR}/main.cpp)
# Testing http support
ADD_EXECUTABLE( server ${PROJECT_SOURCE_DIR}/server.cpp )
FIND_PACKAGE( Boost 1.70 required COMPONENTS thread system )
INCLUDE_DIRECTORIES( ${Boost_INCLUDE_Dirs} )
target_link_libraries ( server LINK_PUBLIC ${Boost_LIBRARIES} )
解决方法
最后，问题很简单。如果可以的话，对于初学者来说，这是一个容易犯的错误，但对于初学者来说，通过常规的Google搜索来破解它几乎是不可能的。
当我发布cmake .时，它默认为64位版本，但假定使用Visual Studio 2019目标。那是错误的。
等效项应该为cmake -G "Visual Studio 15 2017 Win64" .，但不知道这一点，并且按照错误的教程，我改为发布cmake -G "Visual Studio 15 2017" .。默认情况下为32位版本-尽管默认情况下它从未提及此事实。它可以找到增强的功能，但是所有库文件都是64位的，而对于32位则没有用，因此它只是说“我什么都找不到！”。
感谢@Tsyvarev，他应得到答案的功劳。打开调试并逐字符查看搜索到的库文件确实是正确的选择。