如何将 cmake 与 boost asio 一起使用？

Question

我无法让 boost::asio 在我的 c++ 程序中使用 cmake。实际上，我已经尝试并在 Google 上搜索了很多小时，但我无法让它工作！

我想在我的 Ubuntu 18.04 下的 c++ 项目中包含 boost::asio 和一个 cmake 文件。

所以我安装了最新的 CMake (cmake version 3.19.4)，并下载了 boost 1.74 版并执行了

./bootstrap.sh --prefix=/usr/
sudo ./b2 install

安装目录为/home/boost/boost_1_74_0。我的 CMake 文件如下所示：

cmake_minimum_required (VERSION 3.1.0)
# Project name
project (machine_tryout VERSION 1.0)

# Boost (header only)
#set(Boost_DEBUG 1)
set(BOOST_ROOT "$ENV{HOME}/boost/boost_1_74_0")
set(Boost_INCLUDE_DIR  "$ENV{HOME}/boost/boost_1_74_0")
set(Boost_LIBRARY_DIR "$ENV{HOME}/boost/boost_1_74_0/libs")
find_package(Boost REQUIRED Components asio) 
    
# Set Executable
add_executable(${PROJECT_NAME} source/tryout.cpp)

但我得到的一切如下：

vm-umic@vm:~/Projects/tryout/build$ cmake ..
CMake Warning at /snap/cmake/775/share/cmake-3.19/Modules/FindBoost.cmake:2034 (message):
  No header defined for asio; skipping header check (note: header-only
  libraries have no designated component)
Call Stack (most recent call first):
  CMakeLists.txt:27 (find_package)


CMake Error at /snap/cmake/775/share/cmake-3.19/Modules/FindPackageHandleStandardArgs.cmake:218 (message):
  Could NOT find Boost (missing: asio) (found version "1.74.0")
Call Stack (most recent call first):
  /snap/cmake/775/share/cmake-3.19/Modules/FindPackageHandleStandardArgs.cmake:582 (_FPHSA_FAILURE_MESSAGE)
  /snap/cmake/775/share/cmake-3.19/Modules/FindBoost.cmake:2193 (find_package_handle_standard_args)
  CMakeLists.txt:27 (find_package)


-- Configuring incomplete, errors occurred!
See also "/home/vm-umic/Projects/tryout/build/CMakeFiles/CMakeOutput.log".

我到底做错了什么？ CMake 不是告诉我它找到了 Boost 1.74 吗？如果我尝试find_package(Boost REQUIRED)，CMake NOT 会抛出任何错误，但是链接也不起作用。我明确告诉 CMake 在哪里可以找到库，那为什么 CMake 找不到 Boost？

Answer 1

试试这个。

cmake_minimum_required (VERSION 3.1.0)
# Project name
project (machine_tryout VERSION 1.0)

# Boost (header only)
#set(Boost_DEBUG 1)
set(BOOST_ROOT "$ENV{HOME}/boost/boost_1_74_0")
set(Boost_INCLUDE_DIR  "$ENV{HOME}/boost/boost_1_74_0")
set(Boost_LIBRARY_DIR "$ENV{HOME}/boost/boost_1_74_0/libs")
find_package(Boost REQUIRED Components system) 
    
# Set Executable
add_executable(${PROJECT_NAME} source/tryout.cpp)
target_link_libraries(${PROJECT_NAME}
    ${Boost_LIBRARIES})