Question

我有一个 Hello，World 风格的程序，我希望使用CMake以端到端的方式开展更多工作。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。

目录布局如下所示

cmaketest
|- build //I would like to have here the CMake generated IDE files.
|- src
   |- main.cpp
   |- hello.cpp
   |- hello.hpp
|- depends //I would like to have here the built Boost libraries and headers.
|- downloads //This contains the downloaded zip file.
|- temp //Temporary files.

我有以下CMakeLists.txt，目前我生成了Visual Studio 2015项目文件，如下所示：cmake build -G "Visual Studio 14 2015 Win64"。一切都很好，我会开始解决方案，CMake抱怨它无法找到Boost，下载它开始构建（在下面的代码中我设置为获取以前获取的文件）。但是经过一段时间的建设，问题就出现了......

Boost文件似乎以\cmaketest\CMakeFiles\build\Boost-prefix\src\Boost的形式出现在根目录中。我怎么能这些它们被构建到\depends\boost（或者那个效果）以及如何包含要链接到解决方案的库？这个链接是一个单独的问题，我知道如何包含这个奇怪目录中的标题，但它并不是我想要的。
看起来VS IDE首先发出警告，首先找不到Boost标头（稍后参见主程序），然后启动Boost构建。这可以避免吗？
如何让Boost库从VS解决方案中消失？即不是要创建它的项目，而只是依赖于头文件和库？
是否有内置方法可以避免下载Boost软件包（如果已经在磁盘上）？看起来它将在任何情况下被检索，我已经考虑过检查文件是否存在。

main.cpp（我想这是本案例中的相关文件）

//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})

Answer 1

我会尝试给你一些提示，试着回答你的问题。

1）使用此代码段，您应该能够在正确的目录中拥有源代码和构建文件。我保留TMP_DIR "${Cmaketest_SOURCE_DIR}/temp"，但在我的项目中，我不使用该行。

ExternalProject_Add(Boost
    TMP_DIR "${Cmaketest_SOURCE_DIR}/temp"
    DOWNLOAD_DIR "${Cmaketest_SOURCE_DIR}/downloads"
    URL "${Cmaketest_SOURCE_DIR}/downloads/boost_1_63_0.zip"
    URL_HASH "SHA1=${Boost_Sha1}"
    SOURCE_DIR ${Cmaketest_SOURCE_DIR}/downloads/boost_1_63_0
    BUILD_IN_SOURCE 1
    UPDATE_COMMAND ""
    PATCH_COMMAND ""
    CONFIGURE_COMMAND ${Boost_Bootstrap_Command} --without-icu --with_libraries=${Config_Libraries}
    BUILD_COMMAND  ${Boost_b2_Command}
        --prefix="${Cmaketest_SOURCE_DIR}/depends/boost_1_63_0"
        --without-python
        --address-model=64
        --architecture=x64
        --threading=multi
        --link=static
        --variant=release
        --layout=tagged
        --build-type=complete
        -j${N}
    INSTALL_COMMAND ${Boost_b2_Command} --prefix="${Cmaketest_SOURCE_DIR}/depends/boost_1_63_0" --without-python
        --address-model=64
        --architecture=x64
        --threading=multi
        --link=static
        --variant=release
        --layout=tagged
        --build-type=complete
        -j${N} install
    INSTALL_DIR "${Cmaketest_SOURCE_DIR}/depends/boost_1_63_0"
)

set(BOOST_ROOT ${Cmaketest_SOURCE_DIR}/depends/boost_1_63_0)
set(Boost_LIBRARY ${Cmaketest_SOURCE_DIR}/depends/boost_1_63_0/lib)
set(Boost_INCLUDE_DIR ${Cmaketest_SOURCE_DIR}/depends/boost_1_63_0/include)
include_directories(${Boost_INCLUDE_DIR})

要注意你没有调用“install”，所以一旦在“奇怪”目录中构建，文件就不会移动到指定的前缀。另请注意使用${Cmaketest_SOURCE_DIR}而不是之前的。{ 尝试打印两者并查看是否存在差异。

2）为了解决在找不到Boost的情况下你会得到的警告，你应该写：

find_package(Boost QUIET)

3）为了解决这个问题，我想你无法生成项目文件，即没有

cmake build -G "Visual Studio 14 2015 Win64"

只需拥有cmake .或cmake ..，具体取决于您是要进行源内构建还是源外构建。我建议做一些源外构建，但这是你的选择 4）FindBoost.cmake（FindBoost.cmake）使您可以将任意路径传递给Boost目录。您可以在配置中使用它来提示CMake在您提供的位置查找Boost，例如你可以用以下方式调用cmake：

cmake -DBOOST_ROOT=/path_to_cmaketest_dir/depends/boost_1_63_0 ..

如果您的系统可能挑剔，您可以指定所有内容：

cmake -DBOOST_ROOT=/path_to_cmaketest_dir/depends/boost_1_63_0 -DBOOST_LIBRARYDIR=/path_to_cmaketest_dir/depends/boost_1_63_0/lib DBOOST_INCLUDEDIR=/path_to_cmaketest_dir/depends/boost_1_63_0/include ..

请注意，在最后两个片段中，我假设了一个源外构建的配置另请注意，如果您已安装或已下载Boost软件包，则在1）中的剪切代码中使用${Cmaketest_SOURCE_DIR}也应解决4）所以当它找不到Boost时会尝试下载但不会，因为现在cmake应该能够看到文件（.zip）。

Answer 2

请参阅CMaker_Boost，在配置时使用CMake构建Boost。现在它在Linux和Android，gcc和clang上进行了测试。其他系统未经过测试。我希望这会有所帮助。

HelloWorld：使用CMake

2 个答案: