Question

我正在为类分配一个作业，在该作业中，我们需要创建一些可以从2个不同程序访问的共享内存。有一个名为 shm.h 的头文件，其中包含我们需要能够共享的数据类型。到目前为止，我的代码看起来像这样。

shm.h

#ifndef SHM_H
#define SHM_H
//<Define an enum called StatusEnus with the enumerations "INVALID", "VALID" 
and "CONSUMED">
#define enum StatusEnus{INVALID, VALID, CONSUMED} StatusEnus

//<Define a typedef structure with the enum above and an "int" variable 
//called "data">

#define struct ShmData{StatusEnus status; int data;}ShmData;
#define SIZE 8

#endif

server_template

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/types.h>
#include "shm.h"

int main(int argc, char* argv[])
{   
    //void* memPtr;
    int retVal = 0;

    //<Confirm argc is 2 and if not print a usage string.>
    if(argc != 2){
        printf("Please enter 2 arguments5");
    }

    /*<Use the POSIX "shm_open" API to open file descriptor with 
        "O_CREAT | O_RDWR" options and the "0666" permissions> */
        //returns -1 on error
        int file = shm_open("sharedMem", O_CREAT | O_RDWR, 0666);
            if (file == -1) retVal =-1;

    /*<Use the "ftruncate" API to set the size to the size of your 
        structure shm.h>*/
    retVal = ftruncate(file,SIZE);

    //<Use the "mmap" API to memory map the file descriptor>
    void* data = mmap(0, SIZE,PROT_WRITE | PROT_WRITE, MAP_SHARED, file, 0);

    /*<Set the "status" field to INVALID>
    <Set the "data" field to atoi(argv[1])>
    <Set the "status" field to VALID>*/
    ShmData->status = INVALID;
    ShmData->data = atoi(argv[1]);
    ShmData->status = VALID;


  printf("[Server]: Server data Valid... waiting for client\n");

  while(ShmData->status != CONSUMED)
    {
      sleep(1);
    }

  printf("[Server]: Server Data consumed!\n");

  /*<use the "munmap" API to unmap the pointer>

  <use the "close" API to close the file Descriptor>

  <use the "shm_unlink" API to revert the shm_open call above>*/

  printf("[Server]: Server exiting...\n");


  return(retVal);

}

所以我的目标是能够从服务器访问诸如ShmData-> StatusEnus之类的字段，而且还能够从单独的程序访问这些文件。但是，就目前情况而言，我一直在遇到与ShmData减速有关的错误。如何确保正在创建的共享内存包含结构中的enum和int字段？

使用头文件共享内存数据

0 个答案: