C中的消息队列:实现2路通信 [英] message queue in C: implementing 2 way comm

问题描述

我是C语言的学生和初学者.我想使用C linux中的消息队列实现双向通讯.我需要两个队列还是只有一个队列才能完成此任务?

I am a student and a begineer in C. I want to implement 2 way communication using message queue in C linux. Do I need two queues or only one to get this done?

我还想知道是否可以将数据(显示为代码)发送到另一个进程，或者我需要将其声明为字符数组.

Also I would like to know can I send data(shown in code) to another process or i need to declare it as a character array.

typedef struct msg1
{
    int mlen;
    char *data;
}M1;

typedef struct msgbuf
{
    long    mtype;
    M1      *m;
} message_buf;

先谢谢您了:)

推荐答案

Also I would like to know can I send data(shown in code) to another process or i need to declare it as a character array

是的，您可以将数据发送到另一个进程

yes you can send data to another process

喜欢

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXSIZE     128

void die(char *s)
{
  perror(s);
  exit(1);
}

struct msgbuf
{
    long    mtype;
    char    mtext[MAXSIZE];
};

main()
{
    int msqid;
    int msgflg = IPC_CREAT | 0666;
    key_t key;
    struct msgbuf sbuf;
    size_t buflen;

    key = 1234;

    if ((msqid = msgget(key, msgflg )) < 0)   //Get the message queue ID for the given key
      die("msgget");

    //Message Type
    sbuf.mtype = 1;

    printf("Enter a message to add to message queue : ");
    scanf("%[^\n]",sbuf.mtext);
    getchar();

    buflen = strlen(sbuf.mtext) + 1 ;

    if (msgsnd(msqid, &sbuf, buflen, IPC_NOWAIT) < 0)
    {
        printf ("%d, %d, %s, %d\n", msqid, sbuf.mtype, sbuf.mtext, buflen);
        die("msgsnd");
    }

    else
        printf("Message Sent\n");

    exit(0);
}


//IPC_msgq_rcv.c

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdio.h>
#include <stdlib.h>
#define MAXSIZE     128

void die(char *s)
{
  perror(s);
  exit(1);
}

typedef struct msgbuf
{
    long    mtype;
    char    mtext[MAXSIZE];
} ;


main()
{
    int msqid;
    key_t key;
    struct msgbuf rcvbuffer;

    key = 1234;

    if ((msqid = msgget(key, 0666)) < 0)
      die("msgget()");


     //Receive an answer of message type 1.
    if (msgrcv(msqid, &rcvbuffer, MAXSIZE, 1, 0) < 0)
      die("msgrcv");

    printf("%s\n", rcvbuffer.mtext);
    exit(0);
}

如果您了解消息队列，则可以使用Message Queue进行进程间通信.

If you know about message queue, then Message Queue is used for inter-process communication.

对于多个进程之间的双向通信，您还需要多个消息队列

Also for two-way communication between multiple processes you need multiple message queue

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