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

6       explain_adjtimex - explain adjtimex(2) errors
7

SYNOPSIS

9       #include <libexplain/adjtimex.h>
10       const char *explain_adjtimex(struct timex *data);
11       const char *explain_errno_adjtimex(int errnum, struct timex *data);
12       void explain_message_adjtimex(char *message, int message_size, struct
13       timex *data);
14       void explain_message_errno_adjtimex(char *message, int message_size,
15       int errnum, struct timex *data);
16

DESCRIPTION

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

SEE ALSO

178       adjtimex(2)
179               tune kernel clock
180
181       explain_adjtimex_or_die(3)
182               tune kernel clock and report errors
183
185       libexplain version 0.40
186       Copyright (C) 2009 Peter Miller
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190                                                           explain_adjtimex(3)
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