进程通信system V IPC----消息队列1

msg_server.c

#include "comm.h"

int main()
{
     int msg_id=create_msg_queue();
     char buf[_SIZE_];
     while(1)
     {
          memset(buf,0,sizeof(buf));
          printf("please enter >:");
          fgets(buf,sizeof(buf)-1,stdin);
          if( strncmp(buf,"quit",4)==0)
          {
               printf("server bye!\n");
               break;
          }
           send_msg(msg_id,ser_send_type,buf);
           memset(buf,0,sizeof(buf));
           recv_msg(msg_id,cli_send_type,buf);
           printf("client:%s",buf);
      }
      destroy_msg(msg_id);
      return 0;
}

msg_client.c

#include"comm.h"
 int main()
 {
      int msg_id=get_msg_queue();
      if(msg_id < 0){
           return 1;
      }    
    char buf[_SIZE_];
    while(1)
    {
         recv_msg(msg_id,ser_send_type,buf);
         printf("server:%s",buf);
         memset(buf,0,sizeof(buf));
         
         printf("please enter:");
         fgets(buf,sizeof(buf)-1,stdin);
         if(strncmp(buf,"quit",4)==0)
         {
              printf("client bye!\n");
              break;
         }    
         send_msg(msg_id,cli_send_type,buf);
      }    
      destroy_msg(msg_id);
      return 0;
      
 }

comm.c

#include"comm.h"
 const int ser_send_type=1;//server
 const int cli_send_type=2;//client
 int comm_msg_queue(int flag)
 {
      key_t key = ftok(_PATH_NAME_,_PROJ_ID_);
      if(key == -1)
      {
           perror("ftok");
           return -2;
      }
      int msg_id=msgget(key,flag);
      if(msg_id<0)
          perror("msgget");
      return msg_id;
}
int create_msg_queue()
{
      int flag=IPC_CREAT|IPC_EXCL|0664;
     return comm_msg_queue(flag);
 }
 int get_msg_queue()
 {
     int flag=IPC_CREAT;
     return comm_msg_queue(flag);
}

int recv_msg(int msg_id,int type,char* out)
{
    msg_t msg;
    msg.mtype=type;
    size_t ret=msgrcv(msg_id,&msg,sizeof(msg.mtext),type,0);
    if(ret<0)
    {
         perror("msgrcv");
         return 1;
    }
    strcpy(out,msg.mtext);
    return 0;
}
int send_msg(int msg_id,int type,char* msg_in)
{
     msg_t msg;
     msg.mtype=type;
     strncpy(msg.mtext,msg_in, strlen(msg_in)+1);
     size_t  ret=msgsnd(msg_id,&msg,sizeof(msg.mtext),0);
     if(ret<0)
     {
          perror("msgsnd");
               return 2;
      }
      return 0;
 }
 int destroy_msg(int msg_id)
 {
      msgctl(msg_id,IPC_RMID,NULL);
 }

comm.h

#pragma once
#include<stdio.h>
#include<sys/ipc.h>
#include<sys/msg.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include <sys/types.h>
#include<time.h>
extern const  int ser_send_type;//server
extern const int cli_send_type;//client
#define _PATH_NAME_ "/tmp"
#define _PROJ_ID_ 0x111
#define _SIZE_ 512
 
int create_msg_queue();
int get_msg_queue();
int recv_msg(int msg_id,int type,char* out);
  int send_mag(int msg_id,int type,char* in);
  
  typedef struct msgbuf
  {
       long mtype;
       char mtext[_SIZE_];
  } msg_t;

makefile

.PHONY: all clean
all:msg_server msg_client

msg_server:msg_server.o comm.o
	gcc -o $@ $^
msg_client:msg_client.o comm.o	
	gcc -o $@ $^
%.o:%.c
	gcc -c $<

clean:
	rm -rf msg_server msg_client  *.o

编译直接执行make，然后会生成两个可执行程序.
都是根据消息的类型从消息队列中获取对应的消息