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 /* First a scenario with only fgetc, fseek, fputc. */
77 fp = fopen (TESTFILE, "r+");
80 ASSERT (!fwriting (fp));
81 if (fgetc (fp) != 'f')
83 ASSERT (!fwriting (fp));
84 if (fseek (fp, 2, SEEK_CUR))
86 ASSERT (!fwriting (fp));
87 if (fgetc (fp) != 'b')
89 ASSERT (!fwriting (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 ASSERT (!fwriting (fp));
95 if (fputc ('x', fp) != 'x')
97 ASSERT (fwriting (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 fflush when transitioning from write to read,
108 fwriting 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 (!fwriting (fp));
116 if (fgetc (fp) != 'f')
118 ASSERT (!fwriting (fp));
119 if (fseek (fp, 2, SEEK_CUR))
121 ASSERT (!fwriting (fp));
122 if (fgetc (fp) != 'b')
124 ASSERT (!fwriting (fp));
126 ASSERT (!fwriting (fp));
127 if (fgetc (fp) != 'x')
129 ASSERT (!fwriting (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 ASSERT (!fwriting (fp));
135 if (fputc ('z', fp) != 'z')
137 ASSERT (fwriting (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. */
147 fp = fopen (TESTFILE, "a");
150 ASSERT (fwriting (fp));
151 if (fwrite ("bla", 1, 3, fp) < 3)
153 ASSERT (fwriting (fp));
160 fprintf (stderr, "Skipping test: file operations failed.\n");