1explain_fchownat(3) Library Functions Manual explain_fchownat(3)
2
6 explain_fchownat - explain fchownat(2) errors
7
9 #include <libexplain/fchownat.h>
10 const char *explain_fchownat(int dirfd, const char *pathname, int
11 owner, int group, int flags);
12 const char *explain_errno_fchownat(int errnum, int dirfd, const char
13 *pathname, int owner, int group, int flags);
14 void explain_message_fchownat(char *message, int message_size, int
15 dirfd, const char *pathname, int owner, int group, int flags);
16 void explain_message_errno_fchownat(char *message, int message_size,
17 int errnum, int dirfd, const char *pathname, int owner, int group, int
18 flags);
19
21 These functions may be used to obtain explanations for errors returned
22 by the fchownat(2) system call.
23 explain_fchownat
25 const char *explain_fchownat(int dirfd, const char *pathname, int
26 owner, int group, int flags);
27 The explain_fchownat function is used to obtain an explanation of an
29 error returned by the fchownat(2) system call. The least the message
30 will contain is the value of strerror(errno), but usually it will do
31 much better, and indicate the underlying cause in more detail.
32 The errno global variable will be used to obtain the error value to be
34 decoded.
35 dirfd The original dirfd, exactly as passed to the fchownat(2) system
37 call.
38 pathname
40 The original pathname, exactly as passed to the fchownat(2)
41 system call.
42 owner The original owner, exactly as passed to the fchownat(2) system
44 call.
45 group The original group, exactly as passed to the fchownat(2) system
47 call.
48 flags The original flags, exactly as passed to the fchownat(2) system
50 call.
51 Returns:
53 The message explaining the error. This message buffer is shared
54 by all libexplain functions which do not supply a buffer in
55 their argument list. This will be overwritten by the next call
56 to any libexplain function which shares this buffer, including
57 other threads.
58 Note: This function is not thread safe, because it shares a return buf‐
60 fer across all threads, and many other functions in this library.
61 Example: This function is intended to be used in a fashion similar to
63 the following example:
64 if (fchownat(dirfd, pathname, owner, group, flags) < 0)
65 {
66 fprintf(stderr, "%s\n", explain_fchownat(dirfd, pathname,
67 owner, group, flags));
68 exit(EXIT_FAILURE);
69 }
70 The above code example is available pre-packaged as the explain_fchow‐
72 nat_or_die(3) function.
73 explain_errno_fchownat
75 const char *explain_errno_fchownat(int errnum, int dirfd, const char
76 *pathname, int owner, int group, int flags);
77 The explain_errno_fchownat function is used to obtain an explanation of
79 an error returned by the fchownat(2) system call. The least the mes‐
80 sage will contain is the value of strerror(errno), but usually it will
81 do much better, and indicate the underlying cause in more detail.
82 errnum The error value to be decoded, usually obtained from the errno
84 global variable just before this function is called. This is
85 necessary if you need to call any code between the system call
86 to be explained and this function, because many libc functions
87 will alter the value of errno.
88 dirfd The original dirfd, exactly as passed to the fchownat(2) system
90 call.
91 pathname
93 The original pathname, exactly as passed to the fchownat(2)
94 system call.
95 owner The original owner, exactly as passed to the fchownat(2) system
97 call.
98 group The original group, exactly as passed to the fchownat(2) system
100 call.
101 flags The original flags, exactly as passed to the fchownat(2) system
103 call.
104 Returns:
106 The message explaining the error. This message buffer is shared
107 by all libexplain functions which do not supply a buffer in
108 their argument list. This will be overwritten by the next call
109 to any libexplain function which shares this buffer, including
110 other threads.
111 Note: This function is not thread safe, because it shares a return buf‐
113 fer across all threads, and many other functions in this library.
114 Example: This function is intended to be used in a fashion similar to
116 the following example:
117 if (fchownat(dirfd, pathname, owner, group, flags) < 0)
118 {
119 int err = errno;
120 fprintf(stderr, "%s\n", explain_errno_fchownat(err, dirfd,
121 pathname, owner, group, flags));
122 exit(EXIT_FAILURE);
123 }
124 The above code example is available pre-packaged as the explain_fchow‐
126 nat_or_die(3) function.
127 explain_message_fchownat
129 void explain_message_fchownat(char *message, int message_size, int
130 dirfd, const char *pathname, int owner, int group, int flags);
131 The explain_message_fchownat function is used to obtain an explanation
133 of an error returned by the fchownat(2) system call. The least the
134 message will contain is the value of strerror(errno), but usually it
135 will do much better, and indicate the underlying cause in more detail.
136 The errno global variable will be used to obtain the error value to be
138 decoded.
139 message The location in which to store the returned message. If a suit‐
141 able message return buffer is supplied, this function is thread
142 safe.
143 message_size
145 The size in bytes of the location in which to store the
146 returned message.
147 dirfd The original dirfd, exactly as passed to the fchownat(2) system
149 call.
150 pathname
152 The original pathname, exactly as passed to the fchownat(2)
153 system call.
154 owner The original owner, exactly as passed to the fchownat(2) system
156 call.
157 group The original group, exactly as passed to the fchownat(2) system
159 call.
160 flags The original flags, exactly as passed to the fchownat(2) system
162 call.
163 Example: This function is intended to be used in a fashion similar to
165 the following example:
166 if (fchownat(dirfd, pathname, owner, group, flags) < 0)
167 {
168 char message[3000];
169 explain_message_fchownat(message, sizeof(message), dirfd,
170 pathname, owner, group, flags);
171 fprintf(stderr, "%s\n", message);
172 exit(EXIT_FAILURE);
173 }
174 The above code example is available pre-packaged as the explain_fchow‐
176 nat_or_die(3) function.
177 explain_message_errno_fchownat
179 void explain_message_errno_fchownat(char *message, int message_size,
180 int errnum, int dirfd, const char *pathname, int owner, int group, int
181 flags);
182 The explain_message_errno_fchownat function is used to obtain an expla‐
184 nation of an error returned by the fchownat(2) system call. The least
185 the message will contain is the value of strerror(errno), but usually
186 it will do much better, and indicate the underlying cause in more
187 detail.
188 message The location in which to store the returned message. If a suit‐
190 able message return buffer is supplied, this function is thread
191 safe.
192 message_size
194 The size in bytes of the location in which to store the
195 returned message.
196 errnum The error value to be decoded, usually obtained from the errno
198 global variable just before this function is called. This is
199 necessary if you need to call any code between the system call
200 to be explained and this function, because many libc functions
201 will alter the value of errno.
202 dirfd The original dirfd, exactly as passed to the fchownat(2) system
204 call.
205 pathname
207 The original pathname, exactly as passed to the fchownat(2)
208 system call.
209 owner The original owner, exactly as passed to the fchownat(2) system
211 call.
212 group The original group, exactly as passed to the fchownat(2) system
214 call.
215 flags The original flags, exactly as passed to the fchownat(2) system
217 call.
218 Example: This function is intended to be used in a fashion similar to
220 the following example:
221 if (fchownat(dirfd, pathname, owner, group, flags) < 0)
222 {
223 int err = errno;
224 char message[3000];
225 explain_message_errno_fchownat(message, sizeof(message),
226 err, dirfd, pathname, owner, group, flags);
227 fprintf(stderr, "%s\n", message);
228 exit(EXIT_FAILURE);
229 }
230 The above code example is available pre-packaged as the explain_fchow‐
232 nat_or_die(3) function.
233
235 fchownat(2)
236 change ownership of a file relative to a directory
237 explain_fchownat_or_die(3)
239 change ownership of a file relative to a directory and report
240 errors
241
243 libexplain version 1.4
244 Copyright (C) 2013 Peter Miller
245 explain_fchownat(3)