1/* Copyright (C) 1991-2024 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library 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 GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <errno.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22
23#include <support/xstdio.h>
24
25int
26main (int argc, char **argv)
27{
28 static const char hello[] = "Hello, world.\n";
29 static const char replace[] = "Hewwo, world.\n";
30 static const size_t replace_from = 2, replace_to = 4;
31 char filename[FILENAME_MAX];
32 char *name = strrchr (*argv, '/');
33 char buf[BUFSIZ];
34 FILE *f;
35 int lose = 0;
36
37 if (name != NULL)
38 ++name;
39 else
40 name = *argv;
41
42 (void) sprintf (filename, OBJPFX "%s.test", name);
43
44 f = fopen (filename, "w+");
45 if (f == NULL)
46 {
47 perror (filename);
48 exit (1);
49 }
50
51 (void) fputs (hello, f);
52 rewind (f);
53 xfgets (s: buf, size: sizeof (buf), stream: f);
54 rewind (f);
55 (void) fputs (buf, f);
56 rewind (f);
57 {
58 size_t i;
59 for (i = 0; i < replace_from; ++i)
60 {
61 int c = getc (stream: f);
62 if (c == EOF)
63 {
64 printf (format: "EOF at %Zu.\n", i);
65 lose = 1;
66 break;
67 }
68 else if (c != hello[i])
69 {
70 printf (format: "Got '%c' instead of '%c' at %Zu.\n",
71 (unsigned char) c, hello[i], i);
72 lose = 1;
73 break;
74 }
75 }
76 }
77
78 {
79 long int where = ftell (stream: f);
80 if (where == (long int) replace_from)
81 {
82 size_t i;
83 for (i = replace_from; i < replace_to; ++i)
84 if (putc(c: replace[i], stream: f) == EOF)
85 {
86 printf (format: "putc('%c') got %s at %Zu.\n",
87 replace[i], strerror (errno), i);
88 lose = 1;
89 break;
90 }
91 }
92 else if (where == -1L)
93 {
94 printf (format: "ftell got %s (should be at %Zu).\n",
95 strerror (errno), replace_from);
96 lose = 1;
97 }
98 else
99 {
100 printf (format: "ftell returns %lu; should be %Zu.\n", where, replace_from);
101 lose = 1;
102 }
103 }
104
105 if (!lose)
106 {
107 rewind (f);
108 xfgets (s: buf, size: sizeof (buf), stream: f);
109 if (strcmp (buf, replace))
110 {
111 printf (format: "Read \"%s\" instead of \"%s\".\n", buf, replace);
112 lose = 1;
113 }
114 }
115
116 if (lose)
117 printf (format: "Test FAILED! Losing file is \"%s\".\n", filename);
118 else
119 {
120 (void) remove (filename);
121 puts (s: "Test succeeded.");
122 }
123
124 return lose ? EXIT_FAILURE : EXIT_SUCCESS;
125}
126

source code of glibc/stdio-common/test_rdwr.c