消息队列实现从一个进程向另一个进程发送一个数据块的方法

首先是Comm.h的代码

#include<stdio.h>
#include<string.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/msg.h>
#define SERVER_TYPE 1
#define CLIENT_TYPE 2
#define SIZE 128
#define PATHNAME "."
#define PROJ_ID 0x666
struct msgbuf{
 long mtype;
 char mtext[SIZE];
};
int CommMsgQueue(int mgflg);
int CreateMsgQueue();
int GetMsgQueue();

int SendMsg(int msgid, long type, const char *_info);
int RecvMsg();
int DestroyMsgQueue(int msgid);
#endif

Comm.c的代码

#include"Comm.h"
int CommMsgQueue(int msgflg){
 key_t key = ftok(PATHNAME,PROJ_ID);//gets key
 if(key < 0)//failed
 {
  perror("ftok");
  return -1;
 }
 int mspid = msgget(key,msgflg);
    if(mspid < 0)//failed return -1
 {
  perror("msgget");
  return -2;
 }
 return mspid;//success return mspid
}
int CreateMsgQueue()
{
 return CommMsgQueue(IPC_CREAT | IPC_EXCL | 0666);//must new
}
int GetMsgQueue()
{
 return CommMsgQueue(IPC_CREAT);//return has been created
}
int SendMsg(int msgid, long type, const char *_info)
{
 struct msgbuf msg;
 msg.mtype = type;
 strcpy(msg.mtext, _info);
 if(msgsnd(msgid,&msg,sizeof(msg.mtext),0) < 0)
 {
  perror("msgsnd");
  return -1;
 }
 return 0;
}
int RecvMsg(int msgid,long type, char out[])
{
 struct msgbuf msg;
 if(msgrcv(msgid,&msg,sizeof(msg.mtext),type,0) < 0)
 {
  perror("msgrcv");
  return -1;
 }
 strcpy(out,msg.mtext);
 return 0;
}
int DestroyMsgQueue(int msgid)
{
 if(msgctl(msgid, IPC_RMID, NULL) < 0)
 {
  perror("msgctl");
  return -1;
 }
 return 0;//success
}

所有的接口已经实现完毕，现在我们分别实现通信双方的代码

首先是server.c

#include"Comm.h"
int main()
{
 int msgid = CreateMsgQueue();
 printf("msgid: %d\n",msgid);
 char buf[SIZE];
 while(1)
 {
  RecvMsg(msgid,CLIENT_TYPE,buf);
  printf("client# %s\n",buf);
  printf("Please Entry:");
  fflush(stdout);
  ssize_t _s = read(0,buf,sizeof(buf)-1);
  if(_s > 0)
  {
   buf[_s-1] = '\0';
   SendMsg (msgid,SERVER_TYPE,buf);
  }
 }
    DestroyMsgQueue(msgid);
}

接着是client.c

#include"Comm.h"
int main()
{
 int msgid = GetMsgQueue();
 printf("msgid: %d\n",msgid);
 char buf[SIZE];
 while(1)
 {
  printf("Please Entry:");
  fflush(stdout);
  ssize_t _s = read(0,buf,sizeof(buf)-1);
  if(_s > 0)
  {
   buf[_s-1] = '\0';
  }
  SendMsg (msgid,CLIENT_TYPE,buf);
  RecvMsg(msgid,SERVER_TYPE,buf);
  printf("client# %s\n",buf);
 }
}

最后我们来看看makefile文件的编写
​​
最后我们来看看结果吧