commmain.cpp

一个通信模块

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

#define RKEY 0x9001L /*读消息队列的KEY值*/ 
#define WKEY 0x9002L /*写消息队列的KEY值*/ 
#define MSGFLG 0666  /*消息队列访问权限*/ 
#define IPC_WAIT 0   /*等待方式在include文件中未定义*/ 

class MSGBUF{
public:
	long mtype; 
	char mtext[2*1024]; 
}; 

int main()
{
	int rmsqid; /*读消息队列标识符*/ 
	int wmsqid; /*写消息队列标识符*/ 
	/*创建读队列，写队列*/
	/*若读消息队列已存在就取得标识符,否则则创建并取得标识符*/ 
	if ((rmsqid=msgget(RKEY,MSGFLG|IPC_CREAT))<0) 
	{ 
		printf("get read message queue failed\n"); 
		exit(1); 
	}
	
	/*若写消息队列已存在则失败,若不存在则创建并取得标识符*/ 
	if ((wmsqid=msgget(WKEY, MSGFLG|IPC_CREAT))<0) 
	{ 
		printf("get write message queue failed\n"); 
		exit(2); 
	}

	for(int i=0; i<10; i++)
	{
		MSGBUF rBuf;
		/*接收所有类型的消息*/ 
		if (msgrcv(rmsqid,&rBuf,sizeof(MSGBUF)-sizeof(long),0L,IPC_WAIT)>=0) 
		{
			printf("get %ld type message from queue:%s\n", rBuf.mtype,rBuf.mtext); 
			sprintf(rBuf.mtext, "I have recieved %d th msg.", i+1);
			if (msgsnd(wmsqid,&rBuf,sizeof(MSGBUF)-sizeof(long), IPC_NOWAIT)==0) 
				printf("send message OK\n"); 
			else 
			{ 
				printf("send message failed\n"); 
				exit(4); 
			} 
		}
		else 
		{ 
			printf("get message failed\n"); 
			exit(3); 
		}
	}
	return 0;
	
}