linux下使用future的时候报错undefined reference to `pthread_create‘

报错是这样的：

FAILED: test_gdb 
: && /usr/bin/g++ -g  CMakeFiles/test_gdb.dir/gdb_main.cpp.o -o test_gdb   && :
/usr/bin/ld: CMakeFiles/test_gdb.dir/gdb_main.cpp.o: in function `std::thread::thread<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<int (*)()> >, int>::_Async_state_impl(std::thread::_Invoker<std::tuple<int (*)()> >&&)::{lambda()#1}, , void>(std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<int (*)()> >, int>::_Async_state_impl(std::thread::_Invoker<std::tuple<int (*)()> >&&)::{lambda()#1}&&)':
/usr/include/c++/9/thread:126: undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

解决方法：g++编译器添加-pthread参数
在CMakeLists.txt中加上 set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -pthread”)

cmake_minimum_required(VERSION 3.23)
project(test_gdb)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthread")
add_executable(test_gdb gdb_main.cpp)

如果是直接运行编译好的可执行文件，可以这么编译：

g++ -std=c++2a -g -o gdb_main gdb_main.cpp -pthread

编译好之后，直接运行gdb_main文件：

./gdb_main