1 /* Test of freading() function.
2 Copyright (C) 2007 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 2, or (at your option)
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, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
18 /* Written by Bruno Haible <bruno@clisp.org>, 2007. */
26 #define ASSERT(expr) if (!(expr)) abort ();
28 #define TESTFILE "t-freading.tmp"
35 /* Create a file with some contents. Write-only file is never reading. */
36 fp = fopen (TESTFILE, "w");
39 ASSERT (!freading (fp));
40 if (fwrite ("foobarsh", 1, 8, fp) < 8)
42 ASSERT (!freading (fp));
46 /* Open it in read-only mode. Read-only file is always reading. */
47 fp = fopen (TESTFILE, "r");
50 ASSERT (freading (fp));
51 if (fgetc (fp) != 'f')
53 ASSERT (freading (fp));
54 if (fseek (fp, 2, SEEK_CUR))
56 ASSERT (freading (fp));
57 if (fgetc (fp) != 'b')
59 ASSERT (freading (fp));
61 ASSERT (freading (fp));
62 if (fgetc (fp) != 'a')
64 ASSERT (freading (fp));
65 if (fseek (fp, 0, SEEK_END))
67 ASSERT (freading (fp));
71 /* Open it in read-write mode. POSIX requires a reposition (fseek,
72 fsetpos, rewind) or EOF when transitioning from read to write;
73 freading is only deterministic after input or output, but this
74 test case should be portable even on open, after reposition, and
76 /* First a scenario with only fgetc, fseek, fputc. */
77 fp = fopen (TESTFILE, "r+");
80 ASSERT (!freading (fp));
81 if (fgetc (fp) != 'f')
83 ASSERT (freading (fp));
84 if (fseek (fp, 2, SEEK_CUR))
86 /* freading (fp) is undefined here, but fwriting (fp) is false. */
87 if (fgetc (fp) != 'b')
89 ASSERT (freading (fp));
90 /* This fseek call is necessary when switching from reading to writing.
91 See the description of fopen(), ISO C 99 7.19.5.3.(6). */
92 if (fseek (fp, 0, SEEK_CUR) != 0)
94 /* freading (fp) is undefined here, but fwriting (fp) is false. */
95 if (fputc ('x', fp) != 'x')
97 ASSERT (!freading (fp));
98 if (fseek (fp, 0, SEEK_END))
100 /* freading (fp) is undefined here, because on some implementations (e.g.
101 glibc) fseek causes a buffer to be read.
102 fwriting (fp) is undefined as well. */
106 /* Open it in read-write mode. POSIX requires a reposition (fseek,
107 fsetpos, rewind) or EOF when transitioning from read to write;
108 freading is only deterministic after input or output, but this
109 test case should be portable even on open, after reposition, and
111 /* Here a scenario that includes fflush. */
112 fp = fopen (TESTFILE, "r+");
115 ASSERT (!freading (fp));
116 if (fgetc (fp) != 'f')
118 ASSERT (freading (fp));
119 if (fseek (fp, 2, SEEK_CUR))
121 /* freading (fp) is undefined here, but fwriting (fp) is false. */
122 if (fgetc (fp) != 'b')
124 ASSERT (freading (fp));
126 /* freading (fp) is undefined here, but fwriting (fp) is false. */
127 if (fgetc (fp) != 'x')
129 ASSERT (freading (fp));
130 /* This fseek call is necessary when switching from reading to writing.
131 See the description of fopen(), ISO C 99 7.19.5.3.(6). */
132 if (fseek (fp, 0, SEEK_CUR) != 0)
134 /* freading (fp) is undefined here, but fwriting (fp) is false. */
135 if (fputc ('z', fp) != 'z')
137 ASSERT (!freading (fp));
138 if (fseek (fp, 0, SEEK_END))
140 /* freading (fp) is undefined here, because on some implementations (e.g.
141 glibc) fseek causes a buffer to be read.
142 fwriting (fp) is undefined as well. */
146 /* Open it in append mode. Write-only file is never reading. */
147 fp = fopen (TESTFILE, "a");
150 ASSERT (!freading (fp));
151 if (fwrite ("bla", 1, 3, fp) < 3)
153 ASSERT (!freading (fp));
160 fprintf (stderr, "Skipping test: file operations failed.\n");