preadv.c revision 1.1 
1/*	$OpenBSD: preadv.c,v 1.1 2002/02/08 20:04:03 art Exp $	*/
2/*
3 *	Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
4 */
5#include <sys/types.h>
6#include <sys/uio.h>
7#include <stdio.h>
8#include <stdlib.h>
9#include <unistd.h>
10#include <err.h>
11#include <fcntl.h>
12
13int
14main()
15{
16	char temp[] = "/tmp/dup2XXXXXXXXX";
17	const char magic[10] = "0123456789";
18	char c, c1, c2;
19	int fd;
20	struct iovec iv[2];
21
22	if ((fd = mkstemp(temp)) < 0)
23		err(1, "mkstemp");
24	remove(temp);
25
26	if (write(fd, magic, sizeof(magic)) != sizeof(magic))
27		err(1, "write");
28
29	if (lseek(fd, 0, SEEK_SET) != 0)
30		err(1, "lseek");
31
32	if (read(fd, &c, 1) != 1)
33		err(1, "read1");
34
35	if (c != magic[0])
36		errx(1, "read1 %c != %c", c, magic[0]);
37
38	iv[0].iov_base = &c1;
39	iv[0].iov_len = 1;
40	iv[1].iov_base = &c2;
41	iv[1].iov_len = 1;
42
43	if (preadv(fd, iv, 2, 7) != 2)
44		err(1, "pread");
45
46	if (c1 != magic[7])
47		errx(1, "pread %c != %c", c1, magic[7]);
48
49	if (c2 != magic[8])
50		errx(1, "pread %c != %c", c2, magic[7]);
51
52	if (read(fd, &c, 1) != 1)
53		err(1, "read2");
54
55	if (c != magic[1])
56		errx(1, "read2 %c != %c", c, magic[1]);
57
58	return 0;
59}
60