1explain_strndup(3)         Library Functions Manual         explain_strndup(3)
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NAME

6       explain_strndup - explain strndup(3) errors
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SYNOPSIS

9       #include <libexplain/strndup.h>
10       const char *explain_strndup(const char *data, size_t data_size);
11       const char *explain_errno_strndup(int errnum, const char *data, size_t
12       data_size);
13       void explain_message_strndup(char *message, int message_size, const
14       char *data, size_t data_size);
15       void explain_message_errno_strndup(char *message, int message_size, int
16       errnum, const char *data, size_t data_size);
17

DESCRIPTION

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

SEE ALSO

198       strndup(3)
199               duplicate a string
200
201       explain_strndup_or_die(3)
202               duplicate a string and report errors
203
205       libexplain version 0.40
206       Copyright (C) 2009 Peter Miller
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210                                                            explain_strndup(3)
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