linux c POSIX消息队列示例

1.源码实现

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include <unistd.h>
#include <fcntl.h>
#include <mqueue.h>
#include <errno.h>

int main()
{
    mqd_t mqid;
    char *msg = "yuki";
    int i;

    mqid = mq_open("/1.que", O_RDWR|O_CREAT|O_EXCL, 0666, NULL);
    if(mqid < 0)
    {
        if(errno == EEXIST)
        {
            mq_unlink("/1.que");
            mqid = mq_open("/1.que", O_RDWR|O_CREAT|O_EXCL, 0666, NULL);
        }
        else
        {
            perror("open message queue error...");
            return -1;
        }
    }

    if(fork() == 0)
    {
        struct mq_attr mqattr;
        char *buf = NULL;

        mq_getattr(mqid, &mqattr);

        buf = (char *)malloc(mqattr.mq_msgsize);

        for(i=0; i<5; i++)
        {
            if(mq_receive(mqid, buf, mqattr.mq_msgsize, NULL) < 0)
            {
                perror("receive message failed...");
                continue;
            }

            printf("receive message %d: %s\n", i+1, buf);
        }

        free(buf);

        exit(0);
    }

    for(i=0; i<5; i++)
    {
        if(mq_send(mqid, msg, sizeof(msg), i) < 0)
        {
            perror("send message");
            continue;
        }

        printf("send message %d: %s successful\n", i+1, msg);

        sleep(1);
    }

    return 0;
}

2.编译源码

$ gcc -o test test.c -lrt

3.运行及其结果

$ ./test
send message 1: yuki successful
receive message 1: yuki
send message 2: yuki successful
receive message 2: yuki
send message 3: yuki successful
receive message 3: yuki
send message 4: yuki successful
receive message 4: yuki
send message 5: yuki successful
receive message 5: yuki