创建子进程，并使用boost库创建共享内存

好的，下面是使用C++和Boost库创建子进程并使用共享内存的示例代码：

#include <iostream>
#include <boost/interprocess/shared_memory_object.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <boost/interprocess/ipc/message_queue.hpp>
#include <boost/interprocess/sync/interprocess_mutex.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#include <boost/interprocess/sync/named_mutex.hpp>
#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/containers/vector.hpp>
#include <boost/interprocess/allocators/allocator.hpp>
#include <boost/interprocess/exceptions.hpp>
#include <boost/interprocess/ipc/message_queue.hpp>
#include <boost/interprocess/streams/bufferstream.hpp>
#include <boost/interprocess/streams/vectorstream.hpp>
#include <boost/interprocess/ipc/message_queue.hpp>
#include <boost/interprocess/sync/interprocess_semaphore.hpp>
#include <boost/interprocess/sync/scoped_semaphore.hpp>
#include <boost/interprocess/sync/interprocess_condition.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#include <boost/interprocess/sync/interprocess_recursive_mutex.hpp>
#include <boost/process.hpp>

using namespace boost::interprocess;
using namespace boost::process;

int main()
{
    //创建共享内存
    shared_memory_object shm_obj(create_only, "my_shm", read_write);
    shm_obj.truncate(1024); //设置共享内存大小为1024字节

    //映射共享内存到当前进程地址空间
    mapped_region shm_region(shm_obj, read_write);

    //获取共享内存的地址
    void* shm_addr = shm_region.get_address();

    //创建子进程
    child c("path/to/my/child/process");

    //在子进程中操作共享内存
    if (c.id() == 0)
    {
        //映射共享内存到子进程地址空间
        managed_shared_memory shm(open_only, "my_shm");

        //获取共享内存中的vector对象
        typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator;
        typedef vector<int, ShmemAllocator> MyVector;
        ShmemAllocator alloc(shm.get_segment_manager());
        MyVector* myvector = shm.find_or_construct<MyVector>("MyVector")(alloc);
        
        //向vector中添加数据
        myvector->push_back(1);
        myvector->push_back(2);
        myvector->push_back(3);

        //等待主进程读取vector中的数据
        interprocess_semaphore sem(0);
        sem.wait();
    }
    else //在主进程中操作共享内存
    {
        //映射共享内存到主进程地址空间
        managed_shared_memory shm(open_only, "my_shm");

        //获取共享内存中的vector对象
        typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator;
        typedef vector<int, ShmemAllocator> MyVector;
        ShmemAllocator alloc(shm.get_segment_manager());
        MyVector* myvector = shm.find_or_construct<MyVector>("MyVector")(alloc);

        //读取vector中的数据并输出
        for (auto it = myvector->begin(); it != myvector->end(); ++it)
        {
            std::cout << *it << " ";
        }
        std::cout << std::endl;

        //释放共享内存
        shared_memory_object::remove("my_shm");

        //通知子进程可以退出了
        interprocess_semaphore sem(1);
        sem.post();
    }

    return 0;
}

以上代码中使用了Boost库中的`shared_memory_object`、`mapped_region`、`managed_shared_memory`、`allocator`、`vector`、`interprocess_semaphore`等类和函数，分别用于创建和操作共享内存、映射共享内存到进程地址空间、在共享内存中创建对象、向共享内存中添加数据、从共享内存中读取数据、等待和通知进程之间的同步操作等。其中，创建子进程使用了Boost.Process库中的`child`类和构造函数，可以方便地创建和管理子进程。