1 /* Test of fwriting() 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-fwriting.tmp"
35 /* Create a file with some contents. Write-only file is always writing. */
36 fp = fopen (TESTFILE, "w");
39 ASSERT (fwriting (fp));
40 if (fwrite ("foobarsh", 1, 8, fp) < 8)
42 ASSERT (fwriting (fp));
46 /* Open it in read-only mode. Read-only file is never writing. */
47 fp = fopen (TESTFILE, "r");
50 ASSERT (!fwriting (fp));
51 if (fgetc (fp) != 'f')
53 ASSERT (!fwriting (fp));
54 if (fseek (fp, 2, SEEK_CUR))
56 ASSERT (!fwriting (fp));
57 if (fgetc (fp) != 'b')
59 ASSERT (!fwriting (fp));
61 ASSERT (!fwriting (fp));
62 if (fgetc (fp) != 'a')
64 ASSERT (!fwriting (fp));
65 if (fseek (fp, 0, SEEK_END))
67 ASSERT (!fwriting (fp));
71 /* Open it in read-write mode. POSIX requires a reposition (fseek,
72 fsetpos, rewind) or fflush when transitioning from write to read,
73 fwriting is only deterministic after input or output, but this
74 test case should be portable even on open, after reposition, and
76 fp = fopen (TESTFILE, "r+");
79 ASSERT (!fwriting (fp));
80 if (fgetc (fp) != 'f')
82 ASSERT (!fwriting (fp));
83 if (fseek (fp, 2, SEEK_CUR))
85 ASSERT (!fwriting (fp));
86 if (fgetc (fp) != 'b')
88 ASSERT (!fwriting (fp));
89 /* This fseek call is necessary when switching from reading to writing.
90 See the description of fopen(), ISO C 99 7.19.5.3.(6). */
91 if (fseek (fp, 0, SEEK_CUR) != 0)
93 ASSERT (!fwriting (fp));
94 if (fputc ('z', fp) != 'z')
96 ASSERT (fwriting (fp));
97 if (fseek (fp, 0, SEEK_END))
99 /* fwriting (fp) is undefined here, but freading (fp) is false. */
103 /* Open it in read-write mode. POSIX requires a reposition (fseek,
104 fsetpos, rewind) or fflush when transitioning from write to read,
105 fwriting is only deterministic after input or output, but this
106 test case should be portable even on open, after reposition, and
108 fp = fopen (TESTFILE, "r+");
111 ASSERT (!fwriting (fp));
112 if (fgetc (fp) != 'f')
114 ASSERT (!fwriting (fp));
115 if (fseek (fp, 2, SEEK_CUR))
117 ASSERT (!fwriting (fp));
118 if (fgetc (fp) != 'b')
120 ASSERT (!fwriting (fp));
122 ASSERT (!fwriting (fp));
123 if (fgetc (fp) != 'a')
125 ASSERT (!fwriting (fp));
126 /* This fseek call is necessary when switching from reading to writing.
127 See the description of fopen(), ISO C 99 7.19.5.3.(6). */
128 if (fseek (fp, 0, SEEK_CUR) != 0)
130 ASSERT (!fwriting (fp));
131 if (fputc ('z', fp) != 'z')
133 ASSERT (fwriting (fp));
134 if (fseek (fp, 0, SEEK_END))
136 /* fwriting (fp) is undefined here, but freading (fp) is false. */
140 /* Open it in append mode. */
141 fp = fopen (TESTFILE, "a");
144 ASSERT (fwriting (fp));
145 if (fwrite ("bla", 1, 3, fp) < 3)
147 ASSERT (fwriting (fp));
154 fprintf (stderr, "Skipping test: file operations failed.\n");