代碼示例_IPC_共享內存

共享內存

 

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1.封裝接口

#include"shm.h"

//獲取惟一鍵值
key_t get_key(void){
    return ftok("/",0x111);
    }


//建立共享內存
int creat_shm(key_t key, size_t size){
    return  shmget(key, size, 0666|IPC_CREAT);
    }


//獲取共享內存
int get_shm(key_t key, size_t size){
    return shmget(key, size, 0666);
    }


//掛載共享內存
void* map_shm(int shmid){
    return shmat(shmid, NULL, 0);
    }

    
//卸載共享內存
int unmap_shm(void* shm_addr){
    return shmdt(shm_addr);
    }


//刪除共享內存
int delet_shm(int shmid){
    return shmctl(shmid, IPC_RMID, NULL);
    }

 

2.頭文件

#pragma once

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>

extern key_t get_key(void);
extern int creat_shm(key_t key, size_t size);
extern int get_shm(key_t key, size_t size);
extern void* map_shm(int shmid);
extern int unmap_shm(void* shm_addr);
extern int delet_shm(int shmid);

 

3.client

#include"shm.h"

int main(void)
{
    key_t key = get_key(); // 獲取鍵值
    if(key<0){
    perror("get_key failed ");
    exit(1);
    }

    int shmid = creat_shm(key, 1024); // 建立
    if(shmid < 0){
    perror("creat failed ");
    exit(1);
    }

    char* buf = (char*) map_shm(shmid);// 掛載
    if(buf<0){
    perror("map failed ");
    exit(1);
    }

    while(1){                // 讀
    fputs(buf,stdout);
    if(strncmp(buf, "exit",4)==0)
    break;
    sleep(1);
    }

     if(unmap_shm(buf) <0){  // 卸載
    perror("unmap failed ");
    exit(1);
    }

    delet_shm(shmid);          // 刪除

    return 0 ;
}

 

4.server

#include"shm.h"

int main(void)
{
    key_t key = get_key(); // 獲取鍵值
    if(key<0){
    perror("get_key failed");
    exit(1);
    }


    int shmid = get_shm(key,1024); // 獲取
    if(shmid<0){
    perror("get_shm failed");
    exit(1);
    }

    char* buf = (char*)map_shm(shmid); // 掛載
    if(buf<0){
    perror("map  failed");
    exit(1);
    }

    while(1){                // 寫
    fgets(buf,1024,stdin);
    if(strncmp(buf,"exit",4)==0)
        break;
    }

    if(unmap_shm(buf)<0){   // 卸載
    perror("unmap");
    exit(1);
    }

    delet_shm(shmid);      //  刪除
     
    return 0;
}

 

 

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success ！