AppleClang 13编译C++20代码报错：std中无jthread成员

问题场景 #

使用以下配置和代码编译时出现错误：

CMakeLists.txt #

cmake_minimum_required(VERSION 3.14)

project(LocksProject)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_executable(lock_example example.cpp)

example.cpp #

#include <thread>
#include <iostream>

int main() {
    std::jthread {[] {std::cout << "Hi" << std::endl;}};
}

CMake输出 #

-- The C compiler identification is AppleClang 13.0.0.13000027
-- The CXX compiler identification is AppleClang 13.0.0.13000027

编译错误信息 #

error: no member named 'jthread' in namespace 'std'
std::jthread {[] {std::cout << "Hi" << std::endl;}};

解决方法 #

• 升级AppleClang版本：AppleClang 13对C20的支持不完整，std::jthread是C20新增特性，需要AppleClang 14及以上版本才能原生支持。可通过升级Xcode来更新编译器版本。
• 替换为std::thread：若暂时无法升级编译器，将std::jthread替换为std::thread，并手动调用join()管理线程生命周期，修改后的代码如下：

  #include <thread>
  #include <iostream>
  
  int main() {
      std::thread t {[] {std::cout << "Hi" << std::endl;}};
      t.join();
  }
  

• 显式指定C++20编译选项：在CMakeLists.txt中添加额外编译参数，确保编译器明确启用C++20标准，修改后配置如下：

  cmake_minimum_required(VERSION 3.14)
  
  project(LocksProject)
  set(CMAKE_CXX_STANDARD 20)
  set(CMAKE_CXX_STANDARD_REQUIRED ON)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20")
  
  add_executable(lock_example example.cpp)
  

内容的提问来源于stack exchange，提问作者mascai