基于C++的进程间共享内存通信

1、Writer端

　　参照上篇共享内存通信创建过程，内存写入端代码如下所示，其中写入端与读取端的共享内存名称、互斥量名称要保持唯一一致：

// 共享内存数据结构，并保持单字节对齐
#pragma pack(push, 1) 
struct SharedData {
    int count;
    char buffer[256];
};
#pragma pack(pop)

int main()
{
    int a = sizeof(SharedData);
    std::cout << "the value of a is:" << a << std::endl;
    // 创建或打开共享内存
    HANDLE hMapFile = CreateFileMapping(
        INVALID_HANDLE_VALUE,   // 使用物理内存而非文件
        NULL,                   // 默认安全属性
        PAGE_READWRITE,         // 可读可写
        0,                      // 内存大小高位
        sizeof(SharedData),     // 内存大小低位
        L"MySharedMemory"       // 共享内存名称（需唯一）
    );

    if (hMapFile == NULL) {
        std::cerr << "CreateFileMapping failed: " << GetLastError() << std::endl;
        return 1;
    }

    // 将共享内存映射到当前进程地址空间
    SharedData* pSharedData = (SharedData*)MapViewOfFile(
        hMapFile,               // 共享内存句柄
        FILE_MAP_ALL_ACCESS,    // 可读可写
        0, 0,                   // 偏移量
        sizeof(SharedData)      // 映射大小
    );

    if (pSharedData == NULL) {
        std::cerr << "MapViewOfFile failed: " << GetLastError() << std::endl;
        CloseHandle(hMapFile);
        return 1;
    }

    // 创建互斥量（用于同步）
    HANDLE hMutex = CreateMutex(
        NULL,                   // 默认安全属性
        FALSE,                  // 初始状态为未锁定
        L"MyMutex"              // 互斥量名称（需唯一）
    );

    if (hMutex == NULL) {
        std::cerr << "CreateMutex failed: " << GetLastError() << std::endl;
        UnmapViewOfFile(pSharedData);
        CloseHandle(hMapFile);
        return 1;
    }

    std::cout << "Writer started. Press Ctrl+C to exit..." << std::endl;
    int count = 0;

    while (true) {
        // 等待互斥量（加锁）
        WaitForSingleObject(hMutex, INFINITE);

        // 写入数据
        pSharedData->count = count;
        sprintf_s(pSharedData->buffer, "Hello from writer %d", count);
        std::cout << "Writer: Wrote " << count << std::endl;
        count++;

        // 释放互斥量（解锁）
        ReleaseMutex(hMutex);

        Sleep(100); // 等待100毫秒
    }

    // 清理（通常不会执行到这里）
    UnmapViewOfFile(pSharedData);
    CloseHandle(hMapFile);
    CloseHandle(hMutex);

    return 0;
}

2、Reader端

 

#include <iostream>
#include <Windows.h>// 共享内存数据结构
struct SharedData {int count;char buffer[256];
};int main() {// 打开共享内存HANDLE hMapFile = OpenFileMapping(FILE_MAP_ALL_ACCESS,    // 可读可写FALSE,                  // 不继承句柄L"MySharedMemory"       // 共享内存名称
    );if (hMapFile == NULL) {std::cerr << "OpenFileMapping failed: " << GetLastError() << std::endl;return 1;}// 将共享内存映射到当前进程地址空间SharedData* pSharedData = (SharedData*)MapViewOfFile(hMapFile,               // 共享内存句柄FILE_MAP_ALL_ACCESS,    // 可读可写0, 0,                   // 偏移量sizeof(SharedData)      // 映射大小
    );if (pSharedData == NULL) {std::cerr << "MapViewOfFile failed: " << GetLastError() << std::endl;CloseHandle(hMapFile);return 1;}// 打开互斥量HANDLE hMutex = OpenMutex(MUTEX_ALL_ACCESS,       // 访问权限FALSE,                  // 不继承句柄L"MyMutex"              // 互斥量名称
    );if (hMutex == NULL) {std::cerr << "OpenMutex failed: " << GetLastError() << std::endl;UnmapViewOfFile(pSharedData);CloseHandle(hMapFile);return 1;}std::cout << "Reader started. Press Ctrl+C to exit..." << std::endl;int count = -1;while (true) {// 等待互斥量（加锁）
        WaitForSingleObject(hMutex, INFINITE);//读取到序号相同的数据进行丢弃if (count == pSharedData->count){ReleaseMutex(hMutex);continue;}// 读取数据std::cout << "Reader: Read " << pSharedData->count<< ", " << pSharedData->buffer << std::endl;count = pSharedData->count;// 释放互斥量（解锁）
        ReleaseMutex(hMutex);Sleep(100); // 等待100毫秒
    }// 清理
    UnmapViewOfFile(pSharedData);CloseHandle(hMapFile);CloseHandle(hMutex);return 0;
}

 

3、效果演示