FIfo

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>

#define PATH "/tmp/Jan.c"
#define BUFF_SIZE 60

int main(int argc, char **argv)
{
    int fd;
    int ret;
    int pid;
    char wbuff[BUFF_SIZE] = "hello, Jan!";
    char rbuff[BUFF_SIZE];

    if ((ret = mkfifo(PATH, 0644)) < 0) {                   //Create fifo
        perror("mkfifo");
        return -1;
    }

    if ((pid = fork()) < 0) {                                         // Create process
        perror("pid");
        return -1;
    }

    if (pid == 0) {                                               // Child process
        while (1) {
            fd = open(PATH, O_WRONLY);
            write(fd, wbuff, sizeof(wbuff));
            sleep(1);
        }
    } else {                                                           // Father process
        while (1) {
            fd = open(PATH, O_RDONLY);
            read(fd, rbuff, sizeof(rbuff));

            printf("%s\n", rbuff);

            sleep(1);
        }
    }

    return 0;
}

注：本代码中存在一个bug，还未处理，当第一次创建成功之后，后每一次创建时，均需修改PATH
                                                       read      ________________________                                 write
                     father process <------------- |___________Fifo__________|  <------------------child process
                                  ^                                                            ^                                                                   ^
                                       |                                                         |                                                             |
                                               |                                       It's a empty file                                     |
                                                          |                                                                                   |
                                                                     |                                                             |
                                                                                |                                       |
                                                                                           |                  |
                                                                                                     |
                                                                          Create process(father and child)