因为系统默认的fifo权限是000, 所以你需要先修改权限再open
完整的代码如下

read

#include <unistd.h>#include <sys/types.h>#include <sys/stat.h>#include <errno.h>#include <fcntl.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#define FIFO_SERVER "/tmp/myfifo"main(int argc, char** argv) {    char buf_r[100];    int fd;    int nread;    if ((mkfifo(FIFO_SERVER, O_CREAT | O_EXCL |O_RDWR) < 0) && (errno != EEXIST))    {        perror("can not creat fifoserver");        exit(1);    }    char cmd[100];    sprintf(cmd, "chmod 704 %s", FIFO_SERVER);    system(cmd);    printf("preparing for reading bytes...\n");    memset(buf_r, 0, sizeof(buf_r));    fd = open(FIFO_SERVER, O_RDONLY | O_NONBLOCK, 0);    if (fd == -1) {        perror("open");        exit(1);    }    while (1)    {        memset(buf_r, 0, sizeof(buf_r));        if ((nread = read(fd, buf_r, 100)) == -1) {            if (errno == EAGAIN)                printf("no data yet\n");        }        printf("read %s from FIFO\n", buf_r);        sleep(1);    }//    pause();    close(fd);    unlink(FIFO_SERVER);}

write

#include <unistd.h>#include <sys/types.h>#include <sys/stat.h>#include <errno.h>#include <fcntl.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#define FIFO_SERVER "/tmp/myfifo"int main(int argc, char** argv){    int fd;    char w_buf[100];    int nwrite;    fd = open(FIFO_SERVER, O_WRONLY | O_NONBLOCK,0);    if (fd == -1)    {        perror("open error;no reading process");        exit(1);    }    if (argc == 1)    {        printf("please send somenthing\n");        exit(1);    }    strcpy(w_buf, argv[1]);    if ((nwrite = write(fd, w_buf, 100)) == -1)    {        if (errno == EAGAIN)            printf("the fifo has not been read yet.Please try later\n");    }    else        printf("write %s to the fifo\n", w_buf);    close(fd);    return 0;}

运行

先运行reader, 再运行writer

reader

harriszh Fri 1:03@ ~/trunk/cpp/fifo3$ ./readpreparing for reading bytes...read  from FIFOread  from FIFOread  from FIFOread  from FIFOread  from FIFOread  from FIFOread  from FIFOread  from FIFOread abc from FIFOread  from FIFOread  from FIFOread  from FIFOread  from FIFOread  from FIFOread  from FIFOread abc from FIFOread  from FIFOread  from FIFOread  from FIFOread  from FIFO

writer

harriszh Fri 1:03@ ~/trunk/cpp/fifo3$ ./write abcwrite abc to the fifoharriszh Fri 1:03@ ~/trunk/cpp/fifo3$ ./write "abc"write abc to the fifo