1explain_setdomainname(3) Library Functions Manual explain_setdomainname(3)
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6 explain_setdomainname - explain setdomainname(2) errors
7
9 #include <libexplain/setdomainname.h>
10 const char *explain_setdomainname(const char *data, size_t data_size);
11 const char *explain_errno_setdomainname(int errnum, const char *data,
12 size_t data_size);
13 void explain_message_setdomainname(char *message, int message_size,
14 const char *data, size_t data_size);
15 void explain_message_errno_setdomainname(char *message, int mes‐
16 sage_size, int errnum, const char *data, size_t data_size);
17
19 These functions may be used to obtain explanations for errors returned
20 by the setdomainname(2) system call.
21 explain_setdomainname
23 const char *explain_setdomainname(const char *data, size_t data_size);
24 The explain_setdomainname function is used to obtain an explanation of
26 an error returned by the setdomainname(2) system call. The least the
27 message will contain is the value of strerror(errno), but usually it
28 will do much better, and indicate the underlying cause in more detail.
29 The errno global variable will be used to obtain the error value to be
31 decoded.
32 data The original data, exactly as passed to the setdomainname(2)
34 system call.
35 data_size
37 The original data_size, exactly as passed to the setdomain‐
38 name(2) system call.
39 Returns:
41 The message explaining the error. This message buffer is shared
42 by all libexplain functions which do not supply a buffer in
43 their argument list. This will be overwritten by the next call
44 to any libexplain function which shares this buffer, including
45 other threads.
46 Note: This function is not thread safe, because it shares a return buf‐
48 fer across all threads, and many other functions in this library.
49 Example: This function is intended to be used in a fashion similar to
51 the following example:
52 if (setdomainname(data, data_size) < 0)
53 {
54 fprintf(stderr, "%s\n", explain_setdomainname(data,
55 data_size));
56 exit(EXIT_FAILURE);
57 }
58 The above code example is available pre‐packaged as the explain_setdo‐
60 mainname_or_die(3) function.
61 explain_errno_setdomainname
63 const char *explain_errno_setdomainname(int errnum, const char *data,
64 size_t data_size);
65 The explain_errno_setdomainname function is used to obtain an explana‐
67 tion of an error returned by the setdomainname(2) system call. The
68 least the message will contain is the value of strerror(errno), but
69 usually it will do much better, and indicate the underlying cause in
70 more detail.
71 errnum The error value to be decoded, usually obtained from the errno
73 global variable just before this function is called. This is
74 necessary if you need to call any code between the system call
75 to be explained and this function, because many libc functions
76 will alter the value of errno.
77 data The original data, exactly as passed to the setdomainname(2)
79 system call.
80 data_size
82 The original data_size, exactly as passed to the setdomain‐
83 name(2) system call.
84 Returns:
86 The message explaining the error. This message buffer is shared
87 by all libexplain functions which do not supply a buffer in
88 their argument list. This will be overwritten by the next call
89 to any libexplain function which shares this buffer, including
90 other threads.
91 Note: This function is not thread safe, because it shares a return buf‐
93 fer across all threads, and many other functions in this library.
94 Example: This function is intended to be used in a fashion similar to
96 the following example:
97 if (setdomainname(data, data_size) < 0)
98 {
99 int err = errno;
100 fprintf(stderr, "%s\n", explain_errno_setdomainname(err,
101 data, data_size));
102 exit(EXIT_FAILURE);
103 }
104 The above code example is available pre‐packaged as the explain_setdo‐
106 mainname_or_die(3) function.
107 explain_message_setdomainname
109 void explain_message_setdomainname(char *message, int message_size,
110 const char *data, size_t data_size);
111 The explain_message_setdomainname function is used to obtain an expla‐
113 nation of an error returned by the setdomainname(2) system call. The
114 least the message will contain is the value of strerror(errno), but
115 usually it will do much better, and indicate the underlying cause in
116 more detail.
117 The errno global variable will be used to obtain the error value to be
119 decoded.
120 message The location in which to store the returned message. If a suit‐
122 able message return buffer is supplied, this function is thread
123 safe.
124 message_size
126 The size in bytes of the location in which to store the
127 returned message.
128 data The original data, exactly as passed to the setdomainname(2)
130 system call.
131 data_size
133 The original data_size, exactly as passed to the setdomain‐
134 name(2) system call.
135 Example: This function is intended to be used in a fashion similar to
137 the following example:
138 if (setdomainname(data, data_size) < 0)
139 {
140 char message[3000];
141 explain_message_setdomainname(message, sizeof(message),
142 data, data_size);
143 fprintf(stderr, "%s\n", message);
144 exit(EXIT_FAILURE);
145 }
146 The above code example is available pre‐packaged as the explain_setdo‐
148 mainname_or_die(3) function.
149 explain_message_errno_setdomainname
151 void explain_message_errno_setdomainname(char *message, int mes‐
152 sage_size, int errnum, const char *data, size_t data_size);
153 The explain_message_errno_setdomainname function is used to obtain an
155 explanation of an error returned by the setdomainname(2) system call.
156 The least the message will contain is the value of strerror(errno), but
157 usually it will do much better, and indicate the underlying cause in
158 more detail.
159 message The location in which to store the returned message. If a suit‐
161 able message return buffer is supplied, this function is thread
162 safe.
163 message_size
165 The size in bytes of the location in which to store the
166 returned message.
167 errnum The error value to be decoded, usually obtained from the errno
169 global variable just before this function is called. This is
170 necessary if you need to call any code between the system call
171 to be explained and this function, because many libc functions
172 will alter the value of errno.
173 data The original data, exactly as passed to the setdomainname(2)
175 system call.
176 data_size
178 The original data_size, exactly as passed to the setdomain‐
179 name(2) system call.
180 Example: This function is intended to be used in a fashion similar to
182 the following example:
183 if (setdomainname(data, data_size) < 0)
184 {
185 int err = errno;
186 char message[3000];
187 explain_message_errno_setdomainname(message, sizeof(mes‐
188 sage), err, data, data_size);
189 fprintf(stderr, "%s\n", message);
190 exit(EXIT_FAILURE);
191 }
192 The above code example is available pre‐packaged as the explain_setdo‐
194 mainname_or_die(3) function.
195
197 setdomainname(2)
198 set domain name
199 explain_setdomainname_or_die(3)
201 set domain name and report errors
202
204 libexplain version 1.4
205 Copyright (C) 2009 Peter Miller
206 explain_setdomainname(3)