pread.c revision 276415 
1#include "file.h"
2#ifndef lint
3FILE_RCSID("@(#)$File: pread.c,v 1.3 2014/09/15 19:11:25 christos Exp $")
4#endif  /* lint */
5#include <fcntl.h>
6#include <unistd.h>
7
8ssize_t
9pread(int fd, void *buf, size_t len, off_t off) {
10	off_t old;
11	ssize_t rv;
12
13	if ((old = lseek(fd, off, SEEK_SET)) == -1)
14		return -1;
15
16	if ((rv = read(fd, buf, len)) == -1)
17		return -1;
18
19	if (lseek(fd, old, SEEK_SET) == -1)
20		return -1;
21
22	return rv;
23}
24