在CMake项目中使用Boost::Beast实现WebSocket的Boost依赖查找问题

问题详情 #

在CMake项目中使用Boost::Beast开发WebSocket功能时，CMake查找Boost包出现错误。尝试设置Boost_USE_STATIC_LIBS=OFF和ON两种配置均无法解决。

CMake配置代码 #

cmake_minimum_required (VERSION 3.20)

# set the build type
if(NOT CMAKE_BUILD_TYPE)
    set(CMAKE_BUILD_TYPE Release)
endif(NOT CMAKE_BUILD_TYPE)

if(CMAKE_BUILD_TYPE MATCHES Debug)
  message("Debug build.")
elseif(CMAKE_BUILD_TYPE MATCHES Release)
  message("Release build.")
endif()

set(application_name "myProject")
set(CMAKE_CXX_STANDARD 23)
set(application_version "0.0.1")
set(PROJECT_VER ${application_version})

cmake_policy(SET CMP0048 NEW)
cmake_policy(SET CMP0167 NEW)
# cmake_policy(SET CMP0175 NEW)

set(Boost_USE_STATIC_LIBS OFF)
set(Boost_DEBUG ON)

find_package(Boost 1.75.0 REQUIRED COMPONENTS system)
# find_package(OpenSSL REQUIRED)

project (${application_name} LANGUAGES C CXX)

message(STATUS "Boost system found: ${Boost_SYSTEM_FOUND}")

add_subdirectory(ThirdParty)
add_subdirectory(src)
add_subdirectory(main)

执行输出 #

Release build.
-- Found Boost 1.86.0 at /opt/homebrew/lib/cmake/Boost-1.86.0
--   Requested configuration: REQUIRED COMPONENTS system
-- BoostConfig: find_package(boost_headers 1.86.0 EXACT CONFIG REQUIRED  HINTS /opt/homebrew/lib/cmake)
-- Found boost_headers 1.86.0 at /opt/homebrew/lib/cmake/boost_headers-1.86.0
-- BoostConfig: find_package(boost_system 1.86.0 EXACT CONFIG REQUIRED  HINTS /opt/homebrew/lib/cmake)
-- Found boost_system 1.86.0 at /opt/homebrew/lib/cmake/boost_system-1.86.0
CMake Error at /opt/homebrew/lib/cmake/BoostDetectToolset-1.86.0.cmake:5 (string):
  string sub-command REGEX, mode MATCHALL needs at least 5 arguments total to
  command.
Call Stack (most recent call first):
  /opt/homebrew/lib/cmake/boost_system-1.86.0/boost_system-config.cmake:29 (include)
  /opt/homebrew/lib/cmake/Boost-1.86.0/BoostConfig.cmake:141 (find_package)
  /opt/homebrew/lib/cmake/Boost-1.86.0/BoostConfig.cmake:262 (boost_find_component)
  CMakeLists.txt:26 (find_package)


-- Boost toolset is unknown (compiler  )
-- Scanning /opt/homebrew/lib/cmake/boost_system-1.86.0/libboost_system-variant*.cmake
--   Including /opt/homebrew/lib/cmake/boost_system-1.86.0/libboost_system-variant-mt-shared.cmake
--   [x] libboost_system-mt.dylib
CMake Warning (dev) at /opt/homebrew/lib/cmake/boost_system-1.86.0/libboost_system-variant-mt-shared.cmake:63 (add_library):
  ADD_LIBRARY called with SHARED option but the target platform does not
  support dynamic linking.  Building a STATIC library instead.  This may lead
  to problems.
Call Stack (most recent call first):
  /opt/homebrew/lib/cmake/boost_system-1.86.0/boost_system-config.cmake:53 (include)
  /opt/homebrew/lib/cmake/Boost-1.86.0/BoostConfig.cmake:141 (find_package)
  /opt/homebrew/lib/cmake/Boost-1.86.0/BoostConfig.cmake:262 (boost_find_component)
  CMakeLists.txt:26 (find_package)
This warning is for project developers.  Use -Wno-dev to suppress it.

--   Including /opt/homebrew/lib/cmake/boost_system-1.86.0/libboost_system-variant-mt-static.cmake
--   [ ] libboost_system-mt.a
--   Including /opt/homebrew/lib/cmake/boost_system-1.86.0/libboost_system-variant-shared.cmake
--   [ ] libboost_system.dylib
--   Including /opt/homebrew/lib/cmake/boost_system-1.86.0/libboost_system-variant-static.cmake
--   [ ] libboost_system.a
-- Adding boost_system dependencies: headers
-- The C compiler identification is AppleClang 15.0.0.15000309
-- The CXX compiler identification is AppleClang 15.0.0.15000309
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /Library/Developer/CommandLineTools/usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /Library/Developer/CommandLineTools/usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Boost system found: 1

环境信息 #

• cmake version 3.31.1
• macOS Sequoia 15.0

解决办法 #

核心问题 #

错误根源是**find_package(Boost)调用时机过早**，CMake在执行project命令前未完成编译器的识别和初始化，导致Boost的工具集检测脚本BoostDetectToolset-1.86.0.cmake无法获取有效编译器信息，触发正则匹配参数错误。

修改步骤 #

将project命令移至find_package(Boost)之前，确保CMake先识别编译器：

cmake_minimum_required (VERSION 3.20)

# 先声明项目，让CMake初始化编译器信息
project (myProject LANGUAGES C CXX)

# set the build type
if(NOT CMAKE_BUILD_TYPE)
    set(CMAKE_BUILD_TYPE Release)
endif(NOT CMAKE_BUILD_TYPE)

if(CMAKE_BUILD_TYPE MATCHES Debug)
  message("Debug build.")
elseif(CMAKE_BUILD_TYPE MATCHES Release)
  message("Release build.")
endif()

set(application_name "myProject")
set(CMAKE_CXX_STANDARD 23)
set(application_version "0.0.1")
set(PROJECT_VER ${application_version})

cmake_policy(SET CMP0048 NEW)
cmake_policy(SET CMP0167 NEW)
# cmake_policy(SET CMP0175 NEW)

set(Boost_USE_STATIC_LIBS OFF)
set(Boost_DEBUG ON)

find_package(Boost 1.75.0 REQUIRED COMPONENTS system)
# find_package(OpenSSL REQUIRED)

message(STATUS "Boost system found: ${Boost_SYSTEM_FOUND}")

add_subdirectory(ThirdParty)
add_subdirectory(src)
add_subdirectory(main)

额外优化 #

1. 编译器识别正常后，Boost能正确检测到AppleClang工具集，动态链接库的警告会自动消失。
2. 若仍有链接问题，可显式设置Boost_USE_MULTITHREADED=ON（默认已开启），确保链接多线程版本的Boost库。

内容的提问来源于stack exchange，提问作者cinargursoy