HelloWorld:使用CMake下载、构建和链接Boost

我有一个Hello，World风格的程序，我想使用CMake以端到端的方式进行更多的工作。在这种情况下，这意味着我可以下载Boost库，编译它们，最后编译我的小Hello，World并将Boost库链接到它。

目录布局看起来像当前的

cmaketest|-build//我希望这里有CMake生成的IDE文件。|-src|-main.cpp|-你好.cpp|-你好.hpp|-dependents//我希望这里有构建的Boost库和头。|-downloads//其中包含已下载的zip文件。|-temp//临时文件

我有以下CMakeLists.txt，目前我生成的Visual Studio 2015项目文件如下：cmake build -G "Visual Studio 14 2015 Win64"。一切都很好，我将启动解决方案，CMake抱怨它找不到Boost，去下载它开始构建(在下面的代码中，我设置了获取之前获取的文件)。但经过一段时间的建设，问题出现了。。。

1. Boost文件似乎以根目录的形式出现在cmaketestCMakeFilesbuildBoost-prefixsrcBoost中。我如何才能将这些库构建到dependsboost(或达到这种效果)，以及如何包含要链接到解决方案的库？这个链接是我遇到的一个单独的问题，我知道如何包含这个奇怪目录中的头，但这并不是我真正想要的
2. 看起来VSIDE首先发出了Boost标头找不到的警告(请稍后参阅主程序)，然后启动Boost构建。这能避免吗
3. 如何使Boost库从VS解决方案中消失？也就是说，不是为了制作一个项目，而是仅仅依赖于标头和库
4. 如果Boost软件包已经在磁盘上，有没有内置的方法可以避免下载它？看起来它在任何情况下都会被检索到，我已经考虑过检查文件的存在性

main.cpp(我想这是本例中的相关文件)

//The Boost headers are included just to check the linker.
#include "hello.hpp"
#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/date_time/posix_time/posix_time_io.hpp>
#include <iostream>
using std::cout;
using std::endl;
int main()
{
hello helloer;
cout << helloer.greet("World here") << endl;
return EXIT_SUCCESS;
}

然后是CMakeLists.txt文件。

cmake_minimum_required(VERSION 3.6 FATAL_ERROR)
set(CMAKE_VERBOSE_MAKEFILE ON)
project(Cmaketest)
if(POLICY CMP0042)
cmake_policy(SET CMP0042 NEW)
endif()
if(POLICY CMP0066)
cmake_policy(SET CMP0066 NEW)
endif()
# Default build type if none was specified.
if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
set(CMAKE_BUILD_TYPE Debug CACHE STRING "Choose the type of build." FORCE)
message(STATUS "Setting build type to '${CMAKE_BUILD_TYPE} as none was specified.")
# Possible values of build type for CMake GUI.
set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
endif()
# The path to extra modules.
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
# Setup build locations.
if(NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
endif()
set(CMAKE_CURRENT_BINARY_DIR    
${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/build)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)
include(ExternalProject)
include(ProcessorCount)
ProcessorCount(N)
if(NOT N EQUAL 0)
set(CMAKE_BUILD_FLAGS -j${N})
endif()
# set(BOOST_VERSION 1.63.0)
# Boost related settings:    
# https://cmake.org/cmake/help/v3.6/module/FindBoost.html.
# Should one check the environment variables and flags here explicitly
# to remove the complaint about missing Boost library? Or should perhaps
# BOOST_ROOT be set? Point to what?
find_package(Boost)
if(NOT Boost_FOUND)
# It shouldn't hurt to enable extensive diagnostics, just in case.
# Also, a different set of files is downloaded for UNIX and WIN32
# due to file permissions and line-feeds (Windows should handle
# also Unix style line-feeds).
set(Boost_DETAILED_FAILURE_MSG on)
add_definitions(${Boost_LIB_DIAGNOSTIC_DEFINITIONS})
set(Boost_Bootstrap_Command)
if(UNIX)
set(Boost_Url     "http://sourceforge.net/projects/boost/files/boost/1.63.0/boost_1_63_0.tar.gz")
set(Boost_Sha1 "2cecf1848a813de55e5770f324f084c568abca0a")
set(Boost_Bootstrap_Command ./bootstrap.sh)
set(Boost_b2_Command ./b2)
elseif(WIN32)
set(Boost_Url "http://sourceforge.net/projects/boost/files/boost/1.63.0/boost_1_63_0.zip")
set(Boost_Sha1 "4364989afbe6b11f2d5e59df902c3ca4d7851824")
set(Boost_Bootstrap_Command bootstrap.bat)
set(Boost_b2_Command b2.exe)
endif()
set(Config_Libraries "chrono,filesystem,program_options,system,thread,test")
ExternalProject_Add(Boost
TMP_DIR "${CMAKE_CURRENT_SOURCE_DIR}/temp"
DOWNLOAD_DIR "${CMAKE_CURRENT_SOURCE_DIR}/downloads"
URL "${CMAKE_CURRENT_SOURCE_DIR}/downloads/boost_1_63_0.zip"
URL_HASH "SHA1=${Boost_Sha1}"
BUILD_IN_SOURCE 1
UPDATE_COMMAND ""
PATCH_COMMAND ""
CONFIGURE_COMMAND ${Boost_Bootstrap_Command} --without-icu --with_libraries=${Config_Libraries}
BUILD_COMMAND  ${Boost_b2_Command}
# --prefix="${CMAKE_CURRENT_SOURCE_DIR}/depends"
--without-python
--address-model=64
--architecture=x64
--threading=multi
--link=static
--variant=release
--layout=tagged
--build-type=complete
-j${N}
INSTALL_COMMAND ""
# INSTALL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/depends"
#As it happens, these directories are currently empty...
# set(BOOST_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/depends/include/boost-1_63)
# set(Boost_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/depends/boost_1_63/include)
# set(Boost_LIBRARY ${CMAKE_CURRENT_SOURCE_DIR}/depends/boost_1_63/lib)
)
endif()
set(Boost_USE_STATIC_LIBS OFF)
set(Boost_USE_MULTITHREADED ON)
set(Boost_USE_STATIC_RUNTIME OFF)
include_directories(${CMAKE_SOURCE_DIR}/src)
# Grabbing just all the test project files.
file(GLOB SOURCES "src/*.*")
add_executable(cmaketest ${SOURCES})
# TARGET_LINK_LIBRARIES(cmaketest ${Boost_LIBRARY})