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

 1 #ifndef __COMMON_H_
 2 #define __COMMON_H_
 3 
 4 #include <stdio.h>
 5 #include <unistd.h>
 6 #include <stdlib.h>
 7 #include <sys/ipc.h>
 8 #include <sys/msg.h>
 9 #include <sys/types.h>
10 #include <string.h>
11 #include <time.h>
12 
13 #define MSG_SIZE 1024
14 #define FILEPATH "."
15 #define ID       0
16 #define SERVER_TYPE 1
17 #define CLIENT_TYPE 2
18 
19 typedef struct msg_info {
20         long mtype;
21         char mtext[MSG_SIZE];
22 }msginfo;
23 
24 int CreateMessageQueue();
25 int GetMessageQueue();
26 int DeleteMessageQueue(int msgid);
27 int SendDataToMessageQueue(int msg_id, int send_type, char *msg);
28 int ReceiveDataFromMessageQueue(int msg_id, int receive_type, char *out);
29 
30 #endif

common.c

 1 #include "common.h"
 2 
 3 static int CommonMessageQueue(int flags)
 4 {
 5         key_t _key = ftok(FILEPATH, ID);
 6         if(_key == -1) {
 7                 perror("ftok error");
 8                 return 1;
 9         }
10         int _msg_id = msgget(_key, flags);
11         if(_msg_id < 0) {
12                 perror("msgget error");
13                 return 2;
14         }
15         return _msg_id;
16 }
17 
18 int CreateMessageQueue()
19 {
20         return CommonMessageQueue(IPC_CREAT|IPC_EXCL|0666);
21 }
22 
23 int GetMessageQueue()
24 {
25         return CommonMessageQueue(IPC_CREAT);
26 }
27 
28 int DeleteMessageQueue(int msg_id)
29 {
30         if(msgctl(msg_id, IPC_RMID, NULL) < 0)
31                 return -1;
32         return 0;
33 }
34 
35 int SendDataToMessageQueue(int msg_id, int send_type, char *msg)
36 {
37         msginfo buff;
38         buff.mtype = send_type;
39         strcpy(buff.mtext, msg);
40         int msg_snd = msgsnd(msg_id, (void *)&buff, sizeof(buff), 0);
41         if(msg_snd < 0) {
42                 perror("msgsnd error");
43                 return -3;
44         }
45         return 0;
46 }
47 
48 int ReceiveDataFromMessageQueue(int msg_id, int receive_type, char *out)
49 {
50         msginfo buff;
51         int msg_rcv = msgrcv(msg_id, (void *)&buff, sizeof(buff), receive_type, 0);
52         if(msg_rcv < 0) {
53                 perror("msg_rcv error");
54                 return -4;
55         }
56         strcpy(out, buff.mtext);
57         return 0;
58 }

server.c

 1 #include "common.h"
 2 
 3 int main()
 4 {
 5         char buff[MSG_SIZE];
 6         int msg_id = CreateMessageQueue();
 7 
 8         while(1)
 9         {
10                 //send data
11                 printf("server please enter# ");
12                 fflush(stdout);
13                 ssize_t s = read(0, buff, sizeof(buff)-1);
14                 if(s > 0) {
15                         buff[s-1] = 0;
16                         SendDataToMessageQueue(msg_id, SERVER_TYPE, buff);
17                         printf("data has sended,wait receive......
");
18                 } else {
19                         perror("read error");
20                         return 1;
21                 }
22 
23                 //receive data
24                 ReceiveDataFromMessageQueue(msg_id, CLIENT_TYPE, buff);
25                 printf("from client: %s
", buff);
26         }
27         DeleteMessageQueue(msg_id);
28 
29         return 0;
30 }

client:

 1 #include "common.h"
 2 
 3 int main()
 4 {
 5         char buff[MSG_SIZE];
 6         int msg_id = GetMessageQueue();
 7         while(1) {
 8                 //receive data
 9                 ReceiveDataFromMessageQueue(msg_id, SERVER_TYPE, buff);
10                 printf("from server:%s
", buff);
11 
12                 //send data
13                 printf("client please enter# ");
14                 fflush(stdout);
15                 ssize_t s = read(0, buff, sizeof(buff)-1);
16                 if(s <= 0) {
17                         perror("read error");
18                         return 1;
19                 } else {
20                         buff[s-1] = 0;
21                         SendDataToMessageQueue(msg_id, CLIENT_TYPE, buff);
22                         printf("data has sended,wait receive......
");
23                 }
24         }
25         return 0;
26 }

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

无欲速，无见小利。欲速，则不达；见小利，则大事不成。