无法在 Windows 上使用 clang 12 构建 boost asio答案

【问题标题】：Cannot build boost asio with clang 12 on windows无法在 Windows 上使用 clang 12 构建 boost asio
【发布时间】：2021-09-10 21:51:01
【问题描述】：

我的项目设置使用最新的 vcpkg、boost 1.75 和 clang 12。这适用于 MSVC2019 编译器，但在使用最新的 clang 编译时会产生协程错误。这很容易通过这个简单的 cmake 设置重新创建。我测试了不同的手动编译器标志，但都不起作用。

CMakeLists.txt

cmake_minimum_required(VERSION 3.14)

project(cpp_20_compile_test_boost LANGUAGES CXX)

set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_executable(cpp_20_compile_test_boost  main.cpp)

# This check only works for clang
include(CheckCXXCompilerFlag)
check_cxx_compiler_flag("-fcoroutines-ts" support_coroutine)
if(NOT support_coroutine)
    message(FATAL_ERROR "The compiler doesn't support C++ Coroutines")
endif()

# Still not working when setting this:
# set(CMAKE_CXX_FLAGS "-fcoroutines-ts --stdlib=libc++ -Xclang -fconcepts-ts")

# No change when setting this flag either:
# target_compile_definitions(${PROJECT_NAME} PUBLIC _WINDOWS BOOST_ASIO_HAS_STD_COROUTINE)

# ######### BOOST ##########
set(Boost_USE_MULTITHREADED ON)
set(Boost_USE_STATIC_RUNTIME ON)
set(Boost_USE_STATIC_LIBS ON)

find_package(    Boost    COMPONENTS filesystem thread regex date_time chrono    REQUIRED)

target_include_directories(${PROJECT_NAME} PRIVATE ${Boost_INCLUDE_DIRS})
target_link_directories(${PROJECT_NAME} PRIVATE ${Boost_LIBRARY_DIRS})
target_link_libraries(cpp_20_compile_test_boost PRIVATE ${Boost_LIBRARIES})

target_compile_definitions(${PROJECT_NAME} PUBLIC _WINDOWS BOOST_ASIO_HAS_CO_AWAIT  )

main.cpp

#include <SDKDDKVer.h>
#include <boost/asio.hpp>

int main(int argc, char *argv[]){}

错误：

[0/1 ?/sec] Re-running CMake...
-- Configuring done
-- Generating done
-- Build files have been written to: D:/Backup/Code/Qt/build-cpp_20_compile_test_boost-CLANG_K3000_Qt_5_15_2_MSVC2019_64bit-Debug
[1/2 0.3/sec] Building CXX object CMakeFiles/cpp_20_compile_test_boost.dir/main.cpp.obj
FAILED: CMakeFiles/cpp_20_compile_test_boost.dir/main.cpp.obj 
C:\PROGRA~1\LLVM\bin\CLANG_~1.EXE -DBOOST_ASIO_HAS_CO_AWAIT -D_WINDOWS -I. -ID:/Backup/Code/Qt/cpp_20_compile_test_boost -ID:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include -DQT_QML_DEBUG -g -Xclang -gcodeview -O0 -D_DEBUG -D_DLL -D_MT -Xclang --dependent-lib=msvcrtd -DQT_QML_DEBUG -std=gnu++20 -MD -MT CMakeFiles/cpp_20_compile_test_boost.dir/main.cpp.obj -MF CMakeFiles\cpp_20_compile_test_boost.dir\main.cpp.obj.d -o CMakeFiles/cpp_20_compile_test_boost.dir/main.cpp.obj -c D:/Backup/Code/Qt/cpp_20_compile_test_boost/main.cpp
In file included from D:/Backup/Code/Qt/cpp_20_compile_test_boost/main.cpp:2:
In file included from D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio.hpp:23:
D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/awaitable.hpp:37:12: error: no member named 'coroutine_handle' in namespace 'std'
using std::coroutine_handle;
      ~~~~~^
D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/awaitable.hpp:38:12: error: no member named 'suspend_always' in namespace 'std'
using std::suspend_always;
      ~~~~~^
D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/awaitable.hpp:96:15: error: no template named 'coroutine_handle' in namespace 'boost::asio::detail'
      detail::coroutine_handle<detail::awaitable_frame<U, Executor>> h)
      ~~~~~~~~^
In file included from D:/Backup/Code/Qt/cpp_20_compile_test_boost/main.cpp:2:
In file included from D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio.hpp:23:
In file included from D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/awaitable.hpp:131:
D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/impl/awaitable.hpp:256:3: error: no template named 'coroutine_handle'
  coroutine_handle<void> coro_ = nullptr;
  ^
D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/impl/awaitable.hpp:113:26: error: no template named 'coroutine_handle'
      void await_suspend(coroutine_handle<void>) noexcept
                         ^
D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/impl/awaitable.hpp:169:26: error: no template named 'coroutine_handle'
      void await_suspend(coroutine_handle<void>) noexcept
                         ^
D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/impl/awaitable.hpp:205:26: error: no template named 'coroutine_handle'
      void await_suspend(coroutine_handle<void>) noexcept
                         ^
D:/Backup/Code/Qt/MyApp-vcpkg/installed/x64-windows/include\boost/asio/impl/awaitable.hpp:414:8: error: explicit specialization of undeclared template struct 'coroutine_traits'
struct coroutine_traits<boost::asio::awaitable<T, Executor>, Args...>
       ^               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8 errors generated.
ninja: build stopped: subcommand failed.
17:07:47: The process "C:\Program Files\CMake\bin\cmake.exe" exited with code 1.
Error while building/deploying project cpp_20_compile_test_boost (kit: CLANG K3000 Qt 5.15.2 MSVC2019 64bit)
When executing step "Build"

有什么想法吗？

【问题讨论】：

我会说，该错误非常明显且非特定于 Boost。请提取minimal reproducible example，包括（！）用于构建它的命令行。此外，请特别检查 Boost bugtracker 是否存在类似问题。作为这里的新用户，也可以使用tour 并阅读How to Ask。
它是特定于 boost 的，因为它在没有 clang 的情况下支持 clang，甚至完全支持协程。我能够通过在没有协程的情况下构建 asio 来解决这个问题。 github.com/chriskohlhoff/asio/issues/859

标签： c++ windows boost clang coroutine

【解决方案1】：

Boost asio 启用了 COROUTINE 支持，但没有完全支持它，请参阅 https://clang.llvm.org/cxx_status.html。我可以通过禁用 COROUTINE 自己编译 asio 来解决此问题，请参阅 https://github.com/chriskohlhoff/asio/issues/859#issuecomment-870320308

【讨论】：