1explain_fchdir(3) Library Functions Manual explain_fchdir(3)
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6 explain_fchdir - explain fchdir(2) errors
7
9 #include <libexplain/fchdir.h>
10 const char *explain_fchdir(int fildes);
11 void explain_message_fchdir(char *message, int message_size, int
12 fildes);
13 const char *explain_errno_fchdir(int errnum, int fildes);
14 void explain_message_errno_fchdir(char *message, int message_size, int
15 errnum, int fildes);
16
18 These functions may be used to obtain explanations for fchdir(2)
19 errors.
20 explain_fchdir
22 const char *explain_fchdir(int fildes);
23 The explain_fchdir function is used to obtain an explanation of an
25 error returned by the fchdir(2) system call. The least the message
26 will contain is the value of strerror(errno), but usually it will do
27 much better, and indicate the underlying cause in more detail.
28 The errno global variable will be used to obtain the error value to be
30 decoded.
31 This function is intended to be used in a fashion similar to the fol‐
33 lowing example:
34 if (fchdir(fildes) < 0)
35 {
36 fprintf(stderr, '%s0, explain_fchdir(fildes));
37 exit(EXIT_FAILURE);
38 }
39 fildes The original fildes, exactly as passed to the fchdir(2) system
41 call.
42 Returns:
44 The message explaining the error. This message buffer is
45 shared by all libexplain functions which do not supply a buffer
46 in their argument list. This will be overwritten by the next
47 call to any libexplain function which shares this buffer,
48 including other threads.
49 Note: This function is not thread safe, because it shares a return buf‐
51 fer across all threads, and many other functions in this library.
52 explain_errno_fchdir
54 const char *explain_errno_fchdir(int errnum, int fildes);
55 The explain_errno_fchdir function is used to obtain an explanation of
57 an error returned by the fchdir(2) system call. The least the message
58 will contain is the value of strerror(errnum), but usually it will do
59 much better, and indicate the underlying cause in more detail.
60 This function is intended to be used in a fashion similar to the fol‐
62 lowing example:
63 if (fchdir(fildes) < 0)
64 {
65 int err = errno;
66 fprintf(stderr, '%s0, explain_errno_fchdir(err, fildes));
67 exit(EXIT_FAILURE);
68 }
69 errnum The error value to be decoded, usually obtained from the errno
71 global variable just before this function is called. This is
72 necessary if you need to call any code between the system call
73 to be explained and this function, because many libc functions
74 will alter the value of errno.
75 fildes The original fildes, exactly as passed to the fchdir(2) system
77 call.
78 Returns:
80 The message explaining the error. This message buffer is
81 shared by all libexplain functions which do not supply a buffer
82 in their argument list. This will be overwritten by the next
83 call to any libexplain function which shares this buffer,
84 including other threads.
85 Note: This function is not thread safe, because it shares a return buf‐
87 fer across all threads, and many other functions in this library.
88 explain_message_fchdir
90 void explain_message_fchdir(char *message, int message_size, int
91 fildes);
92 The explain_message_fchdir function is used to obtain an explanation of
94 an error returned by the fchdir(2) system call. The least the message
95 will contain is the value of strerror(errno), but usually it will do
96 much better, and indicate the underlying cause in more detail.
97 The errno global variable will be used to obtain the error value to be
99 decoded.
100 This function is intended to be used in a fashion similar to the fol‐
102 lowing example:
103 if (fchdir(fildes) < 0)
104 {
105 char message[3000];
106 explain_message_fchdir(message, sizeof(message), fildes);
107 fprintf(stderr, '%s0, message);
108 exit(EXIT_FAILURE);
109 }
110 message The location in which to store the returned message. Because a
112 message return buffer has been supplied, this function is
113 thread safe.
114 message_size
116 The size in bytes of the location in which to store the
117 returned message.
118 fildes The original fildes, exactly as passed to the fchdir(2) system
120 call.
121 explain_message_errno_fchdir
123 void explain_message_errno_fchdir(char *message, int message_size, int
124 errnum, int fildes);
125 The explain_message_errno_fchdir function is used to obtain an explana‐
127 tion of an error returned by the fchdir(2) system call. The least the
128 message will contain is the value of strerror(errnum), but usually it
129 will do much better, and indicate the underlying cause in more detail.
130 This function is intended to be used in a fashion similar to the fol‐
132 lowing example:
133 if (fchdir(fildes) < 0)
134 {
135 int err = errno;
136 char message[3000];
137 explain_message_errno_fchdir(message, sizeof(message), err,
138 fildes);
139 fprintf(stderr, '%s0, message);
140 exit(EXIT_FAILURE);
141 }
142 message The location in which to store the returned message. Because a
144 message return buffer has been supplied, this function is
145 thread safe.
146 message_size
148 The size in bytes of the location in which to store the
149 returned message.
150 errnum The error value to be decoded, usually obtained from the errno
152 global variable just before this function is called. This is
153 necessary if you need to call any code between the system call
154 to be explained and this function, because many libc functions
155 will alter the value of errno.
156 fildes The original fildes, exactly as passed to the fchdir(2) system
158 call.
159
161 libexplain version 1.4
162 Copyright (C) 2008 Peter Miller
163
165 Written by Peter Miller <pmiller@opensource.org.au>
166 explain_fchdir(3)