1explain_fchown(3)          Library Functions Manual          explain_fchown(3)
2
3
4

NAME

6       explain_fchown - explain fchown(2) errors
7

SYNOPSIS

9       #include <libexplain/fchown.h>
10       const char *explain_fchown(int fildes, int owner, int group);
11       const char *explain_errno_fchown(int errnum, int fildes, int owner, int
12       group);
13       void  explain_message_fchown(char  *message,  int   message_size,   int
14       fildes, int owner, int group);
15       void  explain_message_errno_fchown(char *message, int message_size, int
16       errnum, int fildes, int owner, int group);
17

DESCRIPTION

19       These functions may be used to obtain explanations for errors  returned
20       by the fchown(2) system call.
21
22   explain_fchown
23       const char *explain_fchown(int fildes, int owner, int group);
24
25       The  explain_fchown  function  is  used  to obtain an explanation of an
26       error returned by the fchown(2) system call.   The  least  the  message
27       will  contain  is  the value of strerror(errno), but usually it will do
28       much better, and indicate the underlying cause in more detail.
29
30       The errno global variable will be used to obtain the error value to  be
31       decoded.
32
33       This  function  is intended to be used in a fashion similar to the fol‐
34       lowing example:
35              if (fchown(fildes, owner, group) < 0)
36              {
37                  fprintf(stderr, "%s\n", explain_fchown(fildes, owner, group));
38                  exit(EXIT_FAILURE);
39              }
40
41       The   above   code   example   is   available   pre‐packaged   as   the
42       explain_fchown_or_die(3) function.
43
44       fildes  The  original fildes, exactly as passed to the fchown(2) system
45               call.
46
47       owner   The original owner, exactly as passed to the  fchown(2)  system
48               call.
49
50       group   The  original  group, exactly as passed to the fchown(2) system
51               call.
52
53       Returns:
54               The message explaining  the  error.   This  message  buffer  is
55               shared by all libexplain functions which do not supply a buffer
56               in their argument list.  This will be overwritten by  the  next
57               call  to  any  libexplain  function  which  shares this buffer,
58               including other threads.
59
60       Note: This function is not thread safe, because it shares a return buf‐
61       fer across all threads, and many other functions in this library.
62
63   explain_errno_fchown
64       const char *explain_errno_fchown(int errnum, int fildes, int owner, int
65       group);
66
67       The explain_errno_fchown function is used to obtain an  explanation  of
68       an  error returned by the fchown(2) system call.  The least the message
69       will contain is the value of strerror(errnum), but usually it  will  do
70       much better, and indicate the underlying cause in more detail.
71
72       This  function  is intended to be used in a fashion similar to the fol‐
73       lowing example:
74              if (fchown(fildes, owner, group) < 0)
75              {
76                  int err = errno;
77                  fprintf(stderr, "%s\n",
78                      explain_errno_fchown(err, fildes, owner, group));
79                  exit(EXIT_FAILURE);
80              }
81
82       The   above   code   example   is   available   pre‐packaged   as   the
83       explain_fchown_or_die(3) function.
84
85       errnum  The  error value to be decoded, usually obtained from the errno
86               global variable just before this function is called.   This  is
87               necessary  if you need to call any code between the system call
88               to be explained and this function, because many libc  functions
89               will alter the value of errno.
90
91       fildes  The  original fildes, exactly as passed to the fchown(2) system
92               call.
93
94       owner   The original owner, exactly as passed to the  fchown(2)  system
95               call.
96
97       group   The  original  group, exactly as passed to the fchown(2) system
98               call.
99
100       Returns:
101               The message explaining  the  error.   This  message  buffer  is
102               shared by all libexplain functions which do not supply a buffer
103               in their argument list.  This will be overwritten by  the  next
104               call  to  any  libexplain  function  which  shares this buffer,
105               including other threads.
106
107       Note: This function is not thread safe, because it shares a return buf‐
108       fer across all threads, and many other functions in this library.
109
110   explain_message_fchown
111       void   explain_message_fchown(char   *message,  int  message_size,  int
112       fildes, int owner, int group);
113
114       The explain_message_fchown function may be used to  obtain an  explana‐
115       tion  of an error returned by the fchown(2) system call.  The least the
116       message will contain is the value of strerror(errno),  but  usually  it
117       will do much better, and indicate the underlying cause in more detail.
118
119       The  errno global variable will be used to obtain the error value to be
120       decoded.
121
122       This function is intended to be used in a fashion similar to  the  fol‐
123       lowing example:
124              if (fchown(fildes, owner, group) < 0)
125              {
126                  char message[3000];
127                  explain_message_fchown(message, sizeof(message), fildes, owner, group);
128                  fprintf(stderr, "%s\n", message);
129                  exit(EXIT_FAILURE);
130              }
131
132       The   above   code   example   is   available   pre‐packaged   as   the
133       explain_fchown_or_die(3) function.
134
135       message The location in which to store  the  returned  message.   If  a
136               suitable  message  return  buffer is supplied, this function is
137               thread safe.
138
139       message_size
140               The size in bytes  of  the  location  in  which  to  store  the
141               returned message.
142
143       fildes  The  original fildes, exactly as passed to the fchown(2) system
144               call.
145
146       owner   The original owner, exactly as passed to the  fchown(2)  system
147               call.
148
149       group   The  original  group, exactly as passed to the fchown(2) system
150               call.
151
152   explain_message_errno_fchown
153       void explain_message_errno_fchown(char *message, int message_size,  int
154       errnum, int fildes, int owner, int group);
155
156       The  explain_message_errno_fchown  function  may  be  used to obtain an
157       explanation of an error returned by the  fchown(2)  system  call.   The
158       least  the  message  will contain is the value of strerror(errnum), but
159       usually it will do much better, and indicate the  underlying  cause  in
160       more detail.
161
162       This  function  is intended to be used in a fashion similar to the fol‐
163       lowing example:
164              if (fchown(fildes, owner, group) < 0)
165              {
166                  int err = errno;
167                  char message[3000];
168                  explain_message_errno_fchown(message, sizeof(message),
169                      err, fildes, owner, group);
170                  fprintf(stderr, "%s\n", message);
171                  exit(EXIT_FAILURE);
172              }
173
174       The   above   code   example   is   available   pre‐packaged   as   the
175       explain_fchown_or_die(3) function.
176
177       message The  location  in  which  to  store the returned message.  If a
178               suitable message return buffer is supplied,  this  function  is
179               thread safe.
180
181       message_size
182               The  size  in  bytes  of  the  location  in  which to store the
183               returned message.
184
185       errnum  The error value to be decoded, usually obtained from the  errno
186               global  variable  just before this function is called.  This is
187               necessary if you need to call any code between the system  call
188               to  be explained and this function, because many libc functions
189               will alter the value of errno.
190
191       fildes  The original fildes, exactly as passed to the fchown(2)  system
192               call.
193
194       owner   The  original  owner, exactly as passed to the fchown(2) system
195               call.
196
197       group   The original group, exactly as passed to the  fchown(2)  system
198               call.
199

SEE ALSO

201       fchown(2)
202               change ownership of a file
203
204       explain_fchown_or_die(3)
205               change ownership of a file and report errors
206
208       libexplain version 0.40
209       Copyright (C) 2008 Peter Miller
210
211
212
213                                                             explain_fchown(3)
Impressum