1 /* Test the pread function.
2 Copyright (C) 2009 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Written by Jim Meyering. */
25 #include <sys/types.h>
28 #define ASSERT(expr) \
33 fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
40 #define N (sizeof buf - 1)
45 char const *file = "in";
47 char buf[] = "0123456789";
52 fd = open (file, O_CREAT | O_WRONLY, 0600);
54 ASSERT (write (fd, buf, N) == N);
55 ASSERT (close (fd) == 0);
57 fd = open (file, O_RDONLY);
60 for (pos = 0; pos < 3; pos++)
63 off_t init_pos = lseek (fd, pos, SEEK_SET);
64 ASSERT (init_pos == pos);
66 for (i = 0; i < N; i++)
69 ASSERT (pread (fd, &byte_buf, 1, i) == 1);
70 ASSERT (byte_buf == buf[i]);
71 ASSERT (lseek (fd, 0, SEEK_CUR) == init_pos);
75 ASSERT (close (fd) == 0);