将数据加载到共享内存中

Question

我想知道如何将文本文件中的数据加载到 C 或 C++ 中的共享内存中。我想将文件的内容逐行分配到结构中，例如：

名称：gaimi舞者 编号：443432 地址：123 Southbrook Dr. Mombai, In 电话号码：8876549300

整个文件以此类推，然后将这些结构加载到共享内存中。

我已经尝试了一切，但没有任何效果。我试过strcpy() 和memcpy() 都没有用。

reader.cpp

#include <sys/shm.h>
#include <stdio.h>
#include<string>
#include<cstring>
#include<cstdlib>
using namespace std;

struct Stu_Info{
    char name[30];
    char id[20];
    char address[30];
    char PhoneNumber[20];
};

int main()
{
    // ftok for generating unique key
    key_t key = ftok("shm",6556);

    // shmget returns an identifier in shmid
    id = shmget(key,1024*4,0666|IPC_CREAT);
    //to make sure the shm made correctly
    if (id < 0){
        perror("create: shmget failed");
        exit(1);
    }else{
        cout << "The shm was craeted!!";
    }

    // shmat to attach to shared memory
    char *str = (char*) shmat(id,(void*)0,0);

    cout<<"Write Data : ";
    gets(str);

    printf("Data written in memory: %s\n",str);

    //detach from shared memory
    shmdt(str);    

    return 0;
}

writer.cpp

#include <iostream>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
using namespace std;

int main()
{
    // ftok to generate unique key
    key_t key = ftok("shmfile",65);

    // shmget returns an identifier in shmid
    int id = shmget(key,1024,0666|IPC_CREAT);

    // shmat to attach to shared memory
    char *str = (char*) shmat(id,(void*)0,0);

    printf("Data read from memory: %s\n",str);

    //detach from shared memory
    shmdt(str);

    // destroy the shared memory
    shmctl(id,IPC_RMID,NULL);

    return 0;
}

文本.txt

gaimi舞者 443432 123 Southbrook 孟买博士，在 8876549300 雅尔 S 播放器 465387 赛义夫路 543 号麦纳麦，文学士 7665647833 院长拉玛 456339 908 Sea Ave. 麦纳麦，BA 4556748900 玛雅拉布 677032 654 South 3rd St. Kwait, KW 3425435456 帕特里夏·凯莉 547839 320 Old navy St. Chiacgo, IL 1112332534

Answer 1

我在 Mac 命令行上运行 cpp，我需要使用这种方式执行此操作，并且还将使用信号量方式。我试过这段代码但没有用。

while (getline(myFile,line)) //getline function to get the data line by line
            {
//                  cout << line << "\n"; // to print the content of the file

                  for(int j=0;j<=15;j++){//to create 15 student structs
                       for (int i=0; i<=15;i+4){ // to iterate in every 4 lines for 15 student strcts to save tha name.
                        strcpy(student[j][i].name,line);
                        name = student[j][i].name;
//                        cout <<student[j][i].name<<"\n";
                            memcpy(str, name , strlen(name)); // to load tha data into shared memory
                        }
                        for (int i=1; i<=15;i+4){ // to iterate in every 4 lines for 15 student strcts to save the id.
                            strcpy(student[j][i].id,line);
                            id = student[j][i].id;
                            memcpy(str, id , strlen(id)); // to load tha data into shared memory
                        }
                        for (int i=2; i<=15;i+4){ // to iterate in every 4 lines for 15 student strcts to save the address.
                            strcpy(student[j][i].address,line);
                            address = student[j][i].address;
                            memcpy(str, address , strlen(address)); // to load tha data into shared memory
                        }
                        for (int i=3; i<=15;i+4){ // to iterate in every 4 lines for 15 student strcts to save phone number.
                            strcpy(student[j][i].PhoneNumber,line);
                            PhoneNumber = student[j][i].PhoneNumber;
                            memcpy(str, PhoneNumber , strlen(PhoneNumber)); // to load tha data into shared memory
                        }
                  }
            }

          myFile.close();
    } else{cout << "unable to open a file!";}