1explain_sleep(3) Library Functions Manual explain_sleep(3)
2
6 explain_sleep - explain sleep(3) errors
7
9 #include <libexplain/sleep.h>
10 const char *explain_sleep(unsigned int seconds);
11 const char *explain_errno_sleep(int errnum, unsigned int seconds);
12 void explain_message_sleep(char *message, int message_size, unsigned
13 int seconds);
14 void explain_message_errno_sleep(char *message, int message_size, int
15 errnum, unsigned int seconds);
16
18 These functions may be used to obtain explanations for errors returned
19 by the sleep(3) system call.
20 explain_sleep
22 const char *explain_sleep(unsigned int seconds);
23 The explain_sleep function is used to obtain an explanation of an error
25 returned by the sleep(3) system call. The least the message will con‐
26 tain is the value of strerror(errno), but usually it will do much bet‐
27 ter, and indicate the underlying cause in more detail.
28 The errno global variable will be used to obtain the error value to be
30 decoded.
31 seconds The original seconds, exactly as passed to the sleep(3) system
33 call.
34 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 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 Example: This function is intended to be used in a fashion similar to
46 the following example:
47 unsigned int result = sleep(seconds);
48 if (result < 0)
49 {
50 fprintf(stderr, "%s\n", explain_sleep(seconds));
51 exit(EXIT_FAILURE);
52 }
53 The above code example is available pre-packaged as the
55 explain_sleep_or_die(3) function.
56 explain_errno_sleep
58 const char *explain_errno_sleep(int errnum, unsigned int seconds);
59 The explain_errno_sleep function is used to obtain an explanation of an
61 error returned by the sleep(3) system call. The least the message will
62 contain is the value of strerror(errno), but usually it will do much
63 better, and indicate the underlying cause in more detail.
64 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 seconds The original seconds, exactly as passed to the sleep(3) system
72 call.
73 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 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 Example: This function is intended to be used in a fashion similar to
85 the following example:
86 unsigned int result = sleep(seconds);
87 if (result < 0)
88 {
89 int err = errno;
90 fprintf(stderr, "%s\n", explain_errno_sleep(err, seconds));
91 exit(EXIT_FAILURE);
92 }
93 The above code example is available pre-packaged as the
95 explain_sleep_or_die(3) function.
96 explain_message_sleep
98 void explain_message_sleep(char *message, int message_size, unsigned
99 int seconds);
100 The explain_message_sleep function is used to obtain an explanation of
102 an error returned by the sleep(3) system call. The least the message
103 will contain is the value of strerror(errno), but usually it will do
104 much better, and indicate the underlying cause in more detail.
105 The errno global variable will be used to obtain the error value to be
107 decoded.
108 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 message_size
114 The size in bytes of the location in which to store the
115 returned message.
116 seconds The original seconds, exactly as passed to the sleep(3) system
118 call.
119 Example: This function is intended to be used in a fashion similar to
121 the following example:
122 unsigned int result = sleep(seconds);
123 if (result < 0)
124 {
125 char message[3000];
126 explain_message_sleep(message, sizeof(message), seconds);
127 fprintf(stderr, "%s\n", message);
128 exit(EXIT_FAILURE);
129 }
130 The above code example is available pre-packaged as the
132 explain_sleep_or_die(3) function.
133 explain_message_errno_sleep
135 void explain_message_errno_sleep(char *message, int message_size, int
136 errnum, unsigned int seconds);
137 The explain_message_errno_sleep function is used to obtain an explana‐
139 tion of an error returned by the sleep(3) system call. The least the
140 message will contain is the value of strerror(errno), but usually it
141 will do much better, and indicate the underlying cause in more detail.
142 message The location in which to store the returned message. If a suit‐
144 able message return buffer is supplied, this function is thread
145 safe.
146 message_size
148 The size in bytes of the location in which to store the
149 returned message.
150 errnum The error value to be decoded, usually obtained from the errno
152 global variable just before this function is called. This is
153 necessary if you need to call any code between the system call
154 to be explained and this function, because many libc functions
155 will alter the value of errno.
156 seconds The original seconds, exactly as passed to the sleep(3) system
158 call.
159 Example: This function is intended to be used in a fashion similar to
161 the following example:
162 unsigned int result = sleep(seconds);
163 if (result < 0)
164 {
165 int err = errno;
166 char message[3000];
167 explain_message_errno_sleep(message, sizeof(message), err,
168 seconds);
169 fprintf(stderr, "%s\n", message);
170 exit(EXIT_FAILURE);
171 }
172 The above code example is available pre-packaged as the
174 explain_sleep_or_die(3) function.
175
177 sleep(3)
178 Sleep for the specified number of seconds
179 explain_sleep_or_die(3)
181 Sleep for the specified number of seconds and report errors
182
184 libexplain version 1.4
185 Copyright (C) 2013 Peter Miller
186 explain_sleep(3)