linux操作系统消息队列

int msgrcv(int msqid, struct msgbuf *msgp, size_t msgsz, long msgtyp, int flag):接受消息，msgtyp是期望接收的消息类型。

msgqueue.c文件内容如下；

#include<sys/types.h>
#include<sys/ipc.h>
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<pthread.h> // 增加线程支持

#define BUFSZ 512

struct message{
    long msg_type;
    char msg_text[BUFSZ];
};

#define MSG_SIZE sizeof(struct message)

char app_exit = 0;
void *thread_funtion(void *parg);

int main()
{
    int qid;
    key_t key;
    int len;
    int res;
    pthread_t a_thread;
    struct message msg;

    if((key = ftok(".",'a')) == -1){ // ftok 获得一个key
        perror("ftok");
        exit(1);
    }

    if((qid = msgget(key,IPC_CREAT|0666)) == -1){ // 创建一个消息队列
        perror("msgget");
        exit(1);
    }

    printf("opened queue %d\n",qid);
    puts("Please enter the message to queue:");
    if((fgets(msg.msg_text,BUFSZ,stdin)) == NULL){ // 从标准输入获得buffer
        puts("no message");
        exit(1);
    }
    
    msg.msg_type = getpid();
    len = strlen(msg.msg_text) + sizeof(msg.msg_type);
    if((msgsnd(qid,&msg,len,0)) < 0){ // 发送消息
        perror("message posted");
        exit(1);
    }

    /*
    memset(&msg,0,sizeof(msg)); // 清除内存为0

    if(msgrcv(qid,&msg,len,0) < 0){ // 接收消息
        perror("message recv");
        exit(1);
    }

    printf("message is:%s\n",(&msg)->msg_text);
    if((msgctl(qid,IPC_RMID,NULL))<0){
        perror("msgctl");
        exit(1);
    }
	*/
    res = pthread_create(&a_thread,NULL,thread_funtion,(void *)&qid);
    
    printf("The msgrcv thread is create sucess!\n");

	while((app_exit =  getchar()) != 'e'){sleep(50);}
    
    printf("exit main funtion!\n");
    exit(0);
}

void *thread_funtion(void *parg)
{
    struct message msg;
    int qid;
    
    qid = *((int *)parg);
    memset(&msg,0,MSG_SIZE);
    while(app_exit != 'e'){
        if(msgrcv(qid,&msg,MSG_SIZE) < 0){
            sleep(50);
            continue;
        }
        printf("message is:%s\n",(&msg)->msg_text);
        if(msgctl(qid,IPC_RMID,NULL) < 0){
            perror("msgctl");
        }
        sleep(50);
    }
}

Makefile文件类型如下；

all:msgqueue

# which compiler
CC = gcc

# Where are include file kept
INCLUDE = .

# Where to install
INSTDIR = /usr/local/bin

# Options for development
CFLAGS = -g -Wall -ansi

msgqueue:msgqueue.o
	$(CC) -D_REENTRANT -o msgqueue msgqueue.o -lpthread

msgqueue.o:msgqueue.c
#	$(CC) -I$(INCLUDE) $(CFLAGS) -c msgqueue.c
#	$(CC) -D_REENTRANT -c msgqueue.c -lpthread
	$(CC) -c msgqueue.c

clean:
	-rm msgqueue.o msgqueue

install:msgqueue
	@if [-d $(INSTDIR) ];\
        then \
        cp msgqueue $(INSTDIR);\
        chmod a+x $(INSTDIR)/msgqueue;\
        chmod og-w $(INSTDIR)/msgqueue;\
        echo "Install in $(INSTDIR)";\
    else \
       echo "Sorry,$(INSTDIR) does not exist";\
    fi