1 /* Test of freading() function.
2 Copyright (C) 2007-2009 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 Bruno Haible <bruno@clisp.org>, 2007. */
26 /* None of the files accessed by this test are large, so disable the
27 fseek link warning if we are not using the gnulib fseek module. */
32 #define ASSERT(expr) \
37 fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
44 #define TESTFILE "t-freading.tmp"
51 /* Create a file with some contents. Write-only file is never reading. */
52 fp = fopen (TESTFILE, "w");
55 ASSERT (!freading (fp));
56 if (fwrite ("foobarsh", 1, 8, fp) < 8)
58 ASSERT (!freading (fp));
62 /* Open it in read-only mode. Read-only file is always reading. */
63 fp = fopen (TESTFILE, "r");
66 ASSERT (freading (fp));
67 if (fgetc (fp) != 'f')
69 ASSERT (freading (fp));
70 if (fseek (fp, 2, SEEK_CUR))
72 ASSERT (freading (fp));
73 if (fgetc (fp) != 'b')
75 ASSERT (freading (fp));
77 ASSERT (freading (fp));
78 if (fgetc (fp) != 'a')
80 ASSERT (freading (fp));
81 if (fseek (fp, 0, SEEK_END))
83 ASSERT (freading (fp));
87 /* Open it in read-write mode. POSIX requires a reposition (fseek,
88 fsetpos, rewind) or EOF when transitioning from read to write;
89 freading is only deterministic after input or output, but this
90 test case should be portable even on open, after reposition, and
92 /* First a scenario with only fgetc, fseek, fputc. */
93 fp = fopen (TESTFILE, "r+");
96 ASSERT (!freading (fp));
97 if (fgetc (fp) != 'f')
99 ASSERT (freading (fp));
100 if (fseek (fp, 2, SEEK_CUR))
102 /* freading (fp) is undefined here, but fwriting (fp) is false. */
103 if (fgetc (fp) != 'b')
105 ASSERT (freading (fp));
106 /* This fseek call is necessary when switching from reading to writing.
107 See the description of fopen(), ISO C 99 7.19.5.3.(6). */
108 if (fseek (fp, 0, SEEK_CUR) != 0)
110 /* freading (fp) is undefined here, but fwriting (fp) is false. */
111 if (fputc ('x', fp) != 'x')
113 ASSERT (!freading (fp));
114 if (fseek (fp, 0, SEEK_END))
116 /* freading (fp) is undefined here, because on some implementations (e.g.
117 glibc) fseek causes a buffer to be read.
118 fwriting (fp) is undefined as well. */
122 /* Open it in read-write mode. POSIX requires a reposition (fseek,
123 fsetpos, rewind) or EOF when transitioning from read to write;
124 freading is only deterministic after input or output, but this
125 test case should be portable even on open, after reposition, and
127 /* Here a scenario that includes fflush. */
128 fp = fopen (TESTFILE, "r+");
131 ASSERT (!freading (fp));
132 if (fgetc (fp) != 'f')
134 ASSERT (freading (fp));
135 if (fseek (fp, 2, SEEK_CUR))
137 /* freading (fp) is undefined here, but fwriting (fp) is false. */
138 if (fgetc (fp) != 'b')
140 ASSERT (freading (fp));
142 /* freading (fp) is undefined here, but fwriting (fp) is false. */
143 if (fgetc (fp) != 'x')
145 ASSERT (freading (fp));
146 /* This fseek call is necessary when switching from reading to writing.
147 See the description of fopen(), ISO C 99 7.19.5.3.(6). */
148 if (fseek (fp, 0, SEEK_CUR) != 0)
150 /* freading (fp) is undefined here, but fwriting (fp) is false. */
151 if (fputc ('z', fp) != 'z')
153 ASSERT (!freading (fp));
154 if (fseek (fp, 0, SEEK_END))
156 /* freading (fp) is undefined here, because on some implementations (e.g.
157 glibc) fseek causes a buffer to be read.
158 fwriting (fp) is undefined as well. */
162 /* Open it in append mode. Write-only file is never reading. */
163 fp = fopen (TESTFILE, "a");
166 ASSERT (!freading (fp));
167 if (fwrite ("bla", 1, 3, fp) < 3)
169 ASSERT (!freading (fp));
176 fprintf (stderr, "Skipping test: file operations failed.\n");