linux 消息队列简单例程

1.首先介绍下BUFSIZ这个关键字什么意思：

BUFSIZ[=8192],这个值在你的stdio.h的182行有申明

2.发送端程序

#include<stdlib.h>
#include<stdio.h>
#include<unistd.h>
#include<string.h>

#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/msg.h>

#define MAX_TEXT 512
struct my_msg_st
{
    int my_msg_type;
    char msg_text[MAX_TEXT];
};

int main(int argc,char *argv[])
{
    int running=1;
    struct my_msg_st some_data;
    int msgid;
    char buffer[BUFSIZ];
    
    if((msgid=msgget((key_t)12345,0666|IPC_CREAT))==-1)
    {
        perror("msgget");
        exit(EXIT_FAILURE);
    }

    while(running)
    {
        printf("Enter the mssage to send:");
        fgets(buffer,BUFSIZ,stdin);
        some_data.my_msg_type=1;
        strcpy(some_data.msg_text,buffer);

        if((msgsnd(msgid,(void *)&some_data,MAX_TEXT,0))==-1)
        {
            perror("msgsnd");
            exit(EXIT_FAILURE);
        }
        if(strncmp(buffer,"end",3)==0)
        {
            running=0;
        }
    }
    return 0;
}

3.接收端

//this is the receiver program
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<unistd.h>

#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/msg.h>

struct my_msg_st
{
	int my_msg_type;
	char msg_text[BUFSIZ];
};

int main(int argc,char *argv[])
{
	int running=1;
	int msgid;
	struct my_msg_st some_data;
	int msg_to_receive=0;


	if((msgid=msgget((key_t)12345,0666 | IPC_CREAT))==-1)
	{
		perror("msgget");
		exit(EXIT_FAILURE);
	}

	while(running)
	{
		if(msgrcv(msgid,(void *)&some_data,BUFSIZ,msg_to_receive,0)==-1)
		{
			perror("msgrcv");
			exit(EXIT_FAILURE);
		}
		printf("receiver mssage:%s",some_data.msg_text);
		if(strncmp(some_data.msg_text,"end",3)==0)

			running=0;
	}

	if(msgctl(msgid,IPC_RMID,0)==-1)
	{
		fprintf(stderr,"msgctl(IPC_RMID) failed\n");
		exit(EXIT_FAILURE);
	}
	return 0;
}