/* include writen */#include	"unp.h"ssize_t						/* Write "n" bytes to a descriptor. */writen(int fd, const void *vptr, size_t n){	size_t		nleft;	ssize_t		nwritten;	const char	*ptr;	ptr = vptr;	nleft = n;	while (nleft > 0) {		if ( (nwritten = write(fd, ptr, nleft)) <= 0) {			if (nwritten < 0 && errno == EINTR)				nwritten = 0;		/* and call write() again */			else				return(-1);			/* error */		}		nleft -= nwritten;		ptr   += nwritten;	}	return(n);}/* end writen */voidWriten(int fd, void *ptr, size_t nbytes){	if (writen(fd, ptr, nbytes) != nbytes)		err_sys("writen error");}