spawn: Use special invocation for <spawn.h> on OS/2 kLIBC.
[gnulib.git] / tests / test-freadahead.c
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1 /* Test of freadahead() function.
2 Copyright (C) 2007-2021 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 <https://www.gnu.org/licenses/>. */
17 /* Written by Bruno Haible <bruno@clisp.org>, 2007. */
19 #include <config.h>
21 #include "freadahead.h"
23 #include <stdlib.h>
24 #include <unistd.h>
26 #include "macros.h"
28 int
29 main (int argc, char **argv)
31 int nbytes = atoi (argv[1]);
32 if (nbytes > 0)
34 void *buf = malloc (nbytes);
35 ASSERT (fread (buf, 1, nbytes, stdin) == nbytes);
36 free (buf);
39 if (nbytes == 0)
40 ASSERT (freadahead (stdin) == 0);
41 else
43 if (lseek (0, 0, SEEK_CUR) == nbytes)
44 /* An unbuffered stdio, such as BeOS or on uClibc compiled without
45 __STDIO_BUFFERS. */
46 ASSERT (freadahead (stdin) == 0);
47 else
49 /* Normal buffered stdio. */
50 size_t buffered;
51 int c, c2;
53 ASSERT (freadahead (stdin) != 0);
54 buffered = freadahead (stdin);
56 c = fgetc (stdin);
57 ASSERT (freadahead (stdin) == buffered - 1);
58 ungetc (c, stdin);
59 ASSERT (freadahead (stdin) == buffered);
60 c2 = fgetc (stdin);
61 ASSERT (c2 == c);
62 ASSERT (freadahead (stdin) == buffered - 1);
64 c = '@';
65 ungetc (c, stdin);
66 ASSERT (freadahead (stdin) == buffered);
67 c2 = fgetc (stdin);
68 ASSERT (c2 == c);
69 ASSERT (freadahead (stdin) == buffered - 1);
73 /* Free memory allocated during ungetc(). */
74 fclose (stdin);
76 return 0;