消息队列——The message queue

//消息队列:数据通讯
// 点对多，离线通讯。
// ftok();索取KEY值
//
// msgget();创建
// msgctl();删除
// msgsnd();发送
// msqrcv();接收
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>

#include "proto.h"

int main()
{
int msgid; //
key_t key;
struct msg_st sbuf;

// 获取消息队列关联的键。
key = ftok(KEYPATH,KEYPROJ);
if(key < 0)
{
perror("ftok()");
exit(1);
}

//int msgget(key_t key, int msgflg);
//参数msgflg为:消息队列的建立标志和存取权限
msgid = msgget(key,0);
//success 返回队列标识，failed ,return -1;
if(msgid < 0)
{
perror("msgget()");
exit(1);
}
//mtype :从消息队列内读取的消息形态。（0：消息队列中所有消息都会被
//读取）
sbuf.mtype = 1; /*!!*/
strcpy(sbuf.name,"Alan");
sbuf.math = rand()%100;
sbuf.chinese = rand()%100;
if(msgsnd(msgid,&sbuf,sizeof(sbuf)-sizeof(long),0) < 0)
{
perror("msgsnd");
exit(1);
}

puts("ok!");

exit(0);
}

----------------------------------------------------------------------------------------------------------------

// 消息队列

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

#include "proto.h"

int main()
{
int msgid;
struct msg_st rbuf;
key_t key;

key = ftok(KEYPATH,KEYPROJ);
if(key < 0)
{
perror("ftok()");
exit(1);
}

msgid = msgget(key,IPC_CREAT|0600);
if(msgid < 0)
{
perror("msgget()");
exit(1);
}

while(1)
{
if(msgrcv(msgid,&rbuf,sizeof(rbuf)-sizeof(long),0,0) < 0)
{
perror("msgrcv()");
exit(1);
}
printf("Name:%s\n",rbuf.name);
printf("Math:%d\n",rbuf.math);
printf("Chinese:%d\n",rbuf.chinese);
}

msgctl(msgid,IPC_RMID,NULL);

exit(0);
}

--------------------------------------------------------------------------------------------------------

#ifndef PROTO_H__
#define PROTO_H__

#define KEYPATH "/etc/services"
#define KEYPROJ 'S'

#define NAMESIZE 32

struct msg_st
{
long mtype;
char name[NAMESIZE];
int math;
int chinese;
};

#endif