Boost的文件内存映射

?boost文件内存映射的使用方法

boost_mapping_file.cpp

#include <boost/interprocess/file_mapping.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <iostream>
using namespace boost::interprocess;

int main()
{
    char file_name[64] = {0};
    int count = 1;
    int file_size = 1024 * 1024 * 1024 * 1; // GB
    for(int i=0; i<count; ++i)
    {
        sprintf(file_name, "./files/f_%d", i);
        boost::interprocess::file_handle_t _handle = ipcdetail::create_or_open_file(file_name, read_write, permissions(),false);
        boost::interprocess::ipcdetail::truncate_file(_handle, file_size);
        boost::interprocess::ipcdetail::close_file(_handle);
        file_mapping *mf = new file_mapping(file_name, read_write);
        mapped_region *region = new mapped_region(*mf, read_write);
        void *addr = region->get_address();
        std::cout << addr << std::endl;
        memset(addr, 'h', file_size); // 写入数据，此时占用内存1GB(file_size)
        region->flush();
        getchar();
        _handle=boost::interprocess::ipcdetail::open_existing_file(file_name,read_write,false); // 再次打开文件，写入内容
        boost::interprocess::ipcdetail::set_file_pointer(_handle,0,file_end);
        std::string data;
        data.resize(file_size);
        boost::interprocess::ipcdetail::write_file(_handle,data.c_str(),data.size());
        boost::interprocess::ipcdetail::close_file(_handle); //关闭，扩容完成
        delete region;
        delete mf;
        getchar();
        mf = new file_mapping(file_name, read_write);
        region = new mapped_region(*mf, read_write);
        addr = region->get_address();
        std::cout << addr << std::endl;
        memset((char*)addr+file_size, 'o', file_size);
        region->flush();
    }
    getchar();
    return 0;
}

CMakeLists.txt

CMAKE_MINIMUM_REQUIRED(VERSION 3.0.0)

PROJECT(ctest)

SET (MyDeps $ENV{MyDependsGcc})

SET(SUFFIX .so)

MESSAGE(STATUS "MyDepends is at $ENV{MyDependsGcc}")

SET(INCS ${MyDeps}/include)

SET(LNKS ${MyDeps}/lib)

SET(PLATFORM x64)

SET(PREFIX lib)

SET(CMAKE_CXX_STANDARD 17)

?

INCLUDE_DIRECTORIES(${INCS})

LINK_DIRECTORIES(${LNKS})

LIST(APPEND LIBS

? ? dl

? ? pthread

? ? boost_filesystem

)

ADD_EXECUTABLE(boost_mapping_file boost_mapping_file.cpp)

TARGET_LINK_LIBRARIES(boost_mapping_file ${LIBS})

?

第一个getchar()之前，内存占用

第二个getchar()之前，内存占用

?

最后

这篇文章解释不错，可以参考，linux top命令 实存(RES)与虚存(VIRT)详解_top res-CSDN博客