1explain_fsync(3) Library Functions Manual explain_fsync(3)
2
6 explain_fsync - explain fsync(2) errors
7
9 #include <libexplain/fsync.h>
10 const char *explain_fsync(int fildes);
11 const char *explain_errno_fsync(int errnum, int fildes);
12 void explain_message_fsync(char *message, int message_size, int
13 fildes);
14 void explain_message_errno_fsync(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 fsync(2) system call.
20 explain_fsync
22 const char *explain_fsync(int fildes);
23 The explain_fsync function is used to obtain an explanation of an error
25 returned by the fsync(2) 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 fildes The original fildes, exactly as passed to the fsync(2) 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 (fsync(fildes) < 0)
48 {
49 fprintf(stderr, "%s\n", explain_fsync(fildes));
50 exit(EXIT_FAILURE);
51 }
52 The above code example is available pre‐packaged as the
54 explain_fsync_or_die(3) function.
55 explain_errno_fsync
57 const char *explain_errno_fsync(int errnum, int fildes);
58 The explain_errno_fsync function is used to obtain an explanation of an
60 error returned by the fsync(2) system call. The least the message will
61 contain is the value of strerror(errno), but usually it will do much
62 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 fsync(2) 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 (fsync(fildes) < 0)
86 {
87 int err = errno;
88 fprintf(stderr, "%s\n", explain_errno_fsync(err, fildes));
89 exit(EXIT_FAILURE);
90 }
91 The above code example is available pre‐packaged as the
93 explain_fsync_or_die(3) function.
94 explain_message_fsync
96 void explain_message_fsync(char *message, int message_size, int
97 fildes);
98 The explain_message_fsync function is used to obtain an explanation of
100 an error returned by the fsync(2) system call. The least the message
101 will contain is the value of strerror(errno), but usually it will do
102 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 fsync(2) system
116 call.
117 Example: This function is intended to be used in a fashion similar to
119 the following example:
120 if (fsync(fildes) < 0)
121 {
122 char message[3000];
123 explain_message_fsync(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_fsync_or_die(3) function.
130 explain_message_errno_fsync
132 void explain_message_errno_fsync(char *message, int message_size, int
133 errnum, int fildes);
134 The explain_message_errno_fsync function is used to obtain an explana‐
136 tion of an error returned by the fsync(2) system call. The least the
137 message will contain is the value of strerror(errno), but usually it
138 will do much better, and indicate the underlying cause in more detail.
139 message The location in which to store the returned message. If a suit‐
141 able message return buffer is supplied, this function is thread
142 safe.
143 message_size
145 The size in bytes of the location in which to store the
146 returned message.
147 errnum The error value to be decoded, usually obtained from the errno
149 global variable just before this function is called. This is
150 necessary if you need to call any code between the system call
151 to be explained and this function, because many libc functions
152 will alter the value of errno.
153 fildes The original fildes, exactly as passed to the fsync(2) system
155 call.
156 Example: This function is intended to be used in a fashion similar to
158 the following example:
159 if (fsync(fildes) < 0)
160 {
161 int err = errno;
162 char message[3000];
163 explain_message_errno_fsync(message, sizeof(message), err,
164 fildes);
165 fprintf(stderr, "%s\n", message);
166 exit(EXIT_FAILURE);
167 }
168 The above code example is available pre‐packaged as the
170 explain_fsync_or_die(3) function.
171
173 fsync(2)
174 synchronize a file's in‐core state with storage device
175 explain_fsync_or_die(3)
177 synchronize a file's in‐core state with storage device and
178 report errors
179
181 libexplain version 1.4
182 Copyright (C) 2009 Peter Miller
183 explain_fsync(3)