text: /* include readn */
  #include	"unp.h"
  ssize_t						/* Read "n" bytes from a descriptor. */
  readn(int fd, void *vptr, size_t n)
  {
  	size_t	nleft;
  	ssize_t	nread;
  	char	*ptr;
  
  	ptr = vptr;
  	nleft = n;
  	while (nleft > 0) {
  		if ( (nread = read(fd, ptr, nleft)) < 0) {
  			if (errno == EINTR){
  				printf("333\n");
  				nread = 0;		/* and call read() again */
  			}
  			else
  				return(-1);
  		} else if (nread == 0)
  			break;				/* EOF */
  
  		nleft -= nread;
  		ptr   += nread;
  	}
  	return(n - nleft);		/* return >= 0 */
  }
  /* end readn */
  
  
  