Linux FIFO

fifo_write.c

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

#include <fcntl.h>
#define FIFO "/tmp/myfifo"

int main(void)
{
    int nread = 0;

    int filefd = open("../demoFIFOWrite/test.txt",O_RDONLY);
    char buf[128]={0,};

    //open調用的阻塞 是什麼一回事呢？很簡單，對於以只讀方式（O_RDONLY）打開的FIFO文件，如果open調用是阻塞的（即第二個參數爲O_RDONLY），除非有一個進程以寫方式打開同一個FIFO，否則它不會返回；
    int fifofd = open(FIFO, O_WRONLY);
    if(fifofd == -1)
    {
        perror("open FIFO error");
        return -1;
    }
    while((nread = read(filefd, buf, sizeof(buf))) > 0)
    {
        write(fifofd, buf, nread);
        printf("write fifo %d data\n", nread);
    }
    return 0;
}

fifo_read.c

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

#include <fcntl.h>
#define FIFO "/tmp/myfifo"

int main(void)
{
    int fifofd = open(FIFO, O_RDONLY);
    if(fifofd == -1)
    {
        perror("open FIFO error");
        return -1;
    }
    char buf[128]={0,};
    int nread = 0;
    while((nread = read(fifofd, buf, sizeof(buf) - 1 )) > 0)
    {
        printf("%s",buf);
        memset(buf, 0x00, sizeof(buf));
    }
    close(fifofd);
    //write(STDOUT_FILENO, "\n", 1);
    return 0;
}