linux IPC 消息队列（二）

我在网上想找多进程之间的通信方式，发现有人写的消息队列很好，搬过来：

common.h

#ifndef __COMMON_H_
#define __COMMON_H_

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

#define MSG_SIZE 1024
#define FILEPATH "."
#define ID       0
#define SERVER_TYPE 1
#define CLIENT_TYPE 2

typedef struct msg_info {
        long mtype;
        char mtext[MSG_SIZE];
}msginfo;

int CreateMessageQueue();
int GetMessageQueue();
int DeleteMessageQueue(int msgid);
int SendDataToMessageQueue(int msg_id, int send_type, char *msg);
int ReceiveDataFromMessageQueue(int msg_id, int receive_type, char *out);

#endif

common.c

#include "common.h"

static int CommonMessageQueue(int flags)
{
        key_t _key = ftok(FILEPATH, ID);
        if(_key == -1) {
                perror("ftok error");
                return 1;
        }
        int _msg_id = msgget(_key, flags);
        if(_msg_id < 0) {
                perror("msgget error");
                return 2;
        }
        return _msg_id;
}

int CreateMessageQueue()
{
        return CommonMessageQueue(IPC_CREAT|IPC_EXCL|0666);
}

int GetMessageQueue()
{
        return CommonMessageQueue(IPC_CREAT);
}

int DeleteMessageQueue(int msg_id)
{
        if(msgctl(msg_id, IPC_RMID, NULL) < 0)
                return -1;
        return 0;
}

int SendDataToMessageQueue(int msg_id, int send_type, char *msg)
{
        msginfo buff;
        buff.mtype = send_type;
        strcpy(buff.mtext, msg);
        int msg_snd = msgsnd(msg_id, (void *)&buff, sizeof(buff), 0);
        if(msg_snd < 0) {
                perror("msgsnd error");
                return -3;
        }
        return 0;
}

int ReceiveDataFromMessageQueue(int msg_id, int receive_type, char *out)
{
        msginfo buff;
        int msg_rcv = msgrcv(msg_id, (void *)&buff, sizeof(buff), receive_type, 0);
        if(msg_rcv < 0) {
                perror("msg_rcv error");
                return -4;
        }
        strcpy(out, buff.mtext);
        return 0;
}

server.c

#include "common.h"

int main()
{
        char buff[MSG_SIZE];
        int msg_id = CreateMessageQueue();

        while(1)
        {
                //send data
                printf("server please enter# ");
                fflush(stdout);
                ssize_t s = read(0, buff, sizeof(buff)-1);
                if(s > 0) {
                        buff[s-1] = 0;
                        SendDataToMessageQueue(msg_id, SERVER_TYPE, buff);
                        printf("data has sended,wait receive......
");
                } else {
                        perror("read error");
                        return 1;
                }

                //receive data
                ReceiveDataFromMessageQueue(msg_id, CLIENT_TYPE, buff);
                printf("from client: %s
", buff);
        }
        DeleteMessageQueue(msg_id);

        return 0;
}

client:

#include "common.h"

int main()
{
        char buff[MSG_SIZE];
        int msg_id = GetMessageQueue();
        while(1) {
                //receive data
                ReceiveDataFromMessageQueue(msg_id, SERVER_TYPE, buff);
                printf("from server:%s
", buff);

                //send data
                printf("client please enter# ");
                fflush(stdout);
                ssize_t s = read(0, buff, sizeof(buff)-1);
                if(s <= 0) {
                        perror("read error");
                        return 1;
                } else {
                        buff[s-1] = 0;
                        SendDataToMessageQueue(msg_id, CLIENT_TYPE, buff);
                        printf("data has sended,wait receive......
");
                }
        }
        return 0;
}

Makefile:

all:client server

client: common.c client.c
        gcc -o $@ $^
server: common.c server.c
        gcc -o $@ $^

.PHONY:clean
clean:
        rm -rf client server