1explain_tcdrain(3) Library Functions Manual explain_tcdrain(3)
2
6 explain_tcdrain - explain tcdrain(3) errors
7
9 #include <libexplain/tcdrain.h>
10 const char *explain_tcdrain(int fildes);
11 const char *explain_errno_tcdrain(int errnum, int fildes);
12 void explain_message_tcdrain(char *message, int message_size, int
13 fildes);
14 void explain_message_errno_tcdrain(char *message, int message_size, int
15 errnum, int fildes);
16
18 These functions may be used to obtain explanations for errors returned
19 by the tcdrain(3) system call.
20 explain_tcdrain
22 const char *explain_tcdrain(int fildes);
23 The explain_tcdrain function is used to obtain an explanation of an
25 error returned by the tcdrain(3) 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 The errno global variable will be used to obtain the error value to be
30 decoded.
31 fildes The original fildes, exactly as passed to the tcdrain(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 if (tcdrain(fildes) < 0)
48 {
49 fprintf(stderr, "%s\n", explain_tcdrain(fildes));
50 exit(EXIT_FAILURE);
51 }
52 The above code example is available pre‐packaged as the
54 explain_tcdrain_or_die(3) function.
55 explain_errno_tcdrain
57 const char *explain_errno_tcdrain(int errnum, int fildes);
58 The explain_errno_tcdrain function is used to obtain an explanation of
60 an error returned by the tcdrain(3) system call. The least the message
61 will contain is the value of strerror(errno), but usually it will do
62 much better, and indicate the underlying cause in more detail.
63 errnum The error value to be decoded, usually obtained from the errno
65 global variable just before this function is called. This is
66 necessary if you need to call any code between the system call
67 to be explained and this function, because many libc functions
68 will alter the value of errno.
69 fildes The original fildes, exactly as passed to the tcdrain(3) system
71 call.
72 Returns:
74 The message explaining the error. This message buffer is shared
75 by all libexplain functions which do not supply a buffer in
76 their argument list. This will be overwritten by the next call
77 to any libexplain function which shares this buffer, including
78 other threads.
79 Note: This function is not thread safe, because it shares a return buf‐
81 fer across all threads, and many other functions in this library.
82 Example: This function is intended to be used in a fashion similar to
84 the following example:
85 if (tcdrain(fildes) < 0)
86 {
87 int err = errno;
88 fprintf(stderr, "%s\n", explain_errno_tcdrain(err, fildes));
89 exit(EXIT_FAILURE);
90 }
91 The above code example is available pre‐packaged as the
93 explain_tcdrain_or_die(3) function.
94 explain_message_tcdrain
96 void explain_message_tcdrain(char *message, int message_size, int
97 fildes);
98 The explain_message_tcdrain function is used to obtain an explanation
100 of an error returned by the tcdrain(3) system call. The least the mes‐
101 sage will contain is the value of strerror(errno), but usually it will
102 do much better, and indicate the underlying cause in more detail.
103 The errno global variable will be used to obtain the error value to be
105 decoded.
106 message The location in which to store the returned message. If a suit‐
108 able message return buffer is supplied, this function is thread
109 safe.
110 message_size
112 The size in bytes of the location in which to store the
113 returned message.
114 fildes The original fildes, exactly as passed to the tcdrain(3) system
116 call.
117 Example: This function is intended to be used in a fashion similar to
119 the following example:
120 if (tcdrain(fildes) < 0)
121 {
122 char message[3000];
123 explain_message_tcdrain(message, sizeof(message), fildes);
124 fprintf(stderr, "%s\n", message);
125 exit(EXIT_FAILURE);
126 }
127 The above code example is available pre‐packaged as the
129 explain_tcdrain_or_die(3) function.
130 explain_message_errno_tcdrain
132 void explain_message_errno_tcdrain(char *message, int message_size, int
133 errnum, int fildes);
134 The explain_message_errno_tcdrain function is used to obtain an expla‐
136 nation of an error returned by the tcdrain(3) system call. The least
137 the message will contain is the value of strerror(errno), but usually
138 it will do much better, and indicate the underlying cause in more
139 detail.
140 message The location in which to store the returned message. If a suit‐
142 able message return buffer is supplied, this function is thread
143 safe.
144 message_size
146 The size in bytes of the location in which to store the
147 returned message.
148 errnum The error value to be decoded, usually obtained from the errno
150 global variable just before this function is called. This is
151 necessary if you need to call any code between the system call
152 to be explained and this function, because many libc functions
153 will alter the value of errno.
154 fildes The original fildes, exactly as passed to the tcdrain(3) system
156 call.
157 Example: This function is intended to be used in a fashion similar to
159 the following example:
160 if (tcdrain(fildes) < 0)
161 {
162 int err = errno;
163 char message[3000];
164 explain_message_errno_tcdrain(message, sizeof(message), err,
165 fildes);
166 fprintf(stderr, "%s\n", message);
167 exit(EXIT_FAILURE);
168 }
169 The above code example is available pre‐packaged as the
171 explain_tcdrain_or_die(3) function.
172
174 tcdrain(3)
175 Execute tcdrain(3)
176 explain_tcdrain_or_die(3)
178 Execute tcdrain(3) and report errors
179
181 libexplain version 1.4
182 Copyright (C) 2009 Peter Miller,,,
183 explain_tcdrain(3)