linux read

ssize_t ret;  

while(len !=0 && (ret = read (fd , buf , len ))!=0)
{
   if(ret == -1)
    {
         if(errno == EINTR)
        continue;
        perror("read");
    break;
    }
    len-=ret;
    buf+=ret;

} 

#include <stdio.h>

#include <errno.h>

#include <string.h>

#include <sys/types.h>

#include <fcntl.h>

int

main (int argc, char *argv[])

{

  int fd = open ("read.c", O_RDWR);

  char buff[1024];

  bzero(buff,sizeof(buff));

  char *buf = buff;

  int len = sizeof(buff);

  ssize_t ret = 0;

  while (len != 0 && (ret = read (fd, buf, len)) != 0)

    {

      if (ret == -1)

{

 if (errno == EINTR)

   continue;

 perror ("read");

 break;

}

      printf ("%s", buf);

      len -= ret;

      buf += ret;

    }

  close (fd);

  return 0;

}