source: trunk/src/sed/gnulib-tests/test-fflush2.c@ 3669

Last change on this file since 3669 was 3611, checked in by bird, 10 months ago

vendor/sed/current: GNU sed 4.9 (sed-4.9.tar.xz sha256:6e226b732e1cd739464ad6862bd1a1aba42d7982922da7a53519631d24975181)

File size: 2.8 KB
Line 
1/* Test of POSIX compatible fflush() function.
2 Copyright (C) 2008-2022 Free Software Foundation, Inc.
3
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.
8
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.
13
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/>. */
16
17#include <config.h>
18
19#include <stdio.h>
20
21#include "binary-io.h"
22#include "macros.h"
23
24int
25main (int argc, char **argv)
26{
27 int c;
28
29 /* Avoid the well-known bugs of fflush() on streams in O_TEXT mode
30 on native Windows platforms. */
31 set_binary_mode (0, O_BINARY);
32
33 if (argc > 1)
34 switch (argv[1][0])
35 {
36 case '1':
37 /* Check fflush after a backup ungetc() call. This is case 1a in
38 terms of
39 <https://lists.gnu.org/r/bug-gnulib/2008-03/msg00131.html>,
40 according to the Austin Group's resolution on 2009-01-08. */
41
42 c = fgetc (stdin);
43 ASSERT (c == '#');
44
45 c = fgetc (stdin);
46 ASSERT (c == '!');
47
48 /* Here the file-position indicator must be 2. */
49
50 c = ungetc ('!', stdin);
51 ASSERT (c == '!');
52
53 fflush (stdin);
54
55 /* Here the file-position indicator must be 1. */
56
57 c = fgetc (stdin);
58 ASSERT (c == '!');
59
60 c = fgetc (stdin);
61 ASSERT (c == '/');
62
63 return 0;
64
65 case '2':
66 /* Check fflush after a non-backup ungetc() call. This is case 2a in
67 terms of
68 <https://lists.gnu.org/r/bug-gnulib/2008-03/msg00131.html>,
69 according to the Austin Group's resolution on 2009-01-08. */
70 /* Check that fflush after a non-backup ungetc() call discards the
71 ungetc buffer. This is mandated by POSIX
72 <https://pubs.opengroup.org/onlinepubs/9699919799/functions/fflush.html>:
73 "...any characters pushed back onto the stream by ungetc()
74 or ungetwc() that have not subsequently been read from the
75 stream shall be discarded..." */
76
77 c = fgetc (stdin);
78 ASSERT (c == '#');
79
80 c = fgetc (stdin);
81 ASSERT (c == '!');
82
83 /* Here the file-position indicator must be 2. */
84
85 c = ungetc ('@', stdin);
86 ASSERT (c == '@');
87
88 fflush (stdin);
89
90 /* Here the file-position indicator must be 1. */
91
92 c = fgetc (stdin);
93 ASSERT (c == '!');
94
95 c = fgetc (stdin);
96 ASSERT (c == '/');
97
98 return 0;
99 }
100
101 return 1;
102}
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