1explain_mknod(3) Library Functions Manual explain_mknod(3)
2
6 explain_mknod - explain mknod(2) errors
7
9 #include <libexplain/mknod.h>
10 const char *explain_mknod(const char *pathname, mode_t mode, dev_t
11 dev);
12 const char *explain_errno_mknod(int errnum, const char *pathname,
13 mode_t mode, dev_t dev);
14 void explain_message_mknod(char *message, int message_size, const char
15 *pathname, mode_t mode, dev_t dev);
16 void explain_message_errno_mknod(char *message, int message_size, int
17 errnum, const char *pathname, mode_t mode, dev_t dev);
18
20 These functions may be used to obtain explanations for errors returned
21 by the mknod(2) system call.
22 explain_mknod
24 const char *explain_mknod(const char *pathname, mode_t mode, dev_t
25 dev);
26 The explain_mknod function is used to obtain an explanation of an error
28 returned by the mknod(2) system call. The least the message will con‐
29 tain is the value of strerror(errno), but usually it will do much bet‐
30 ter, and indicate the underlying cause in more detail.
31 The errno global variable will be used to obtain the error value to be
33 decoded.
34 pathname
36 The original pathname, exactly as passed to the mknod(2) system
37 call.
38 mode The original mode, exactly as passed to the mknod(2) system
40 call.
41 dev The original dev, exactly as passed to the mknod(2) system
43 call.
44 Returns:
46 The message explaining the error. This message buffer is shared
47 by all libexplain functions which do not supply a buffer in
48 their argument list. This will be overwritten by the next call
49 to any libexplain function which shares this buffer, including
50 other threads.
51 Note: This function is not thread safe, because it shares a return buf‐
53 fer across all threads, and many other functions in this library.
54 Example: This function is intended to be used in a fashion similar to
56 the following example:
57 if (mknod(pathname, mode, dev) < 0)
58 {
59 fprintf(stderr, "%s\n", explain_mknod(pathname, mode, dev));
60 exit(EXIT_FAILURE);
61 }
62 The above code example is available pre‐packaged as the
64 explain_mknod_or_die(3) function.
65 explain_errno_mknod
67 const char *explain_errno_mknod(int errnum, const char *pathname,
68 mode_t mode, dev_t dev);
69 The explain_errno_mknod function is used to obtain an explanation of an
71 error returned by the mknod(2) system call. The least the message will
72 contain is the value of strerror(errno), but usually it will do much
73 better, and indicate the underlying cause in more detail.
74 errnum The error value to be decoded, usually obtained from the errno
76 global variable just before this function is called. This is
77 necessary if you need to call any code between the system call
78 to be explained and this function, because many libc functions
79 will alter the value of errno.
80 pathname
82 The original pathname, exactly as passed to the mknod(2) system
83 call.
84 mode The original mode, exactly as passed to the mknod(2) system
86 call.
87 dev The original dev, exactly as passed to the mknod(2) system
89 call.
90 Returns:
92 The message explaining the error. This message buffer is shared
93 by all libexplain functions which do not supply a buffer in
94 their argument list. This will be overwritten by the next call
95 to any libexplain function which shares this buffer, including
96 other threads.
97 Note: This function is not thread safe, because it shares a return buf‐
99 fer across all threads, and many other functions in this library.
100 Example: This function is intended to be used in a fashion similar to
102 the following example:
103 if (mknod(pathname, mode, dev) < 0)
104 {
105 int err = errno;
106 fprintf(stderr, "%s\n", explain_errno_mknod(err, pathname,
107 mode, dev));
108 exit(EXIT_FAILURE);
109 }
110 The above code example is available pre‐packaged as the
112 explain_mknod_or_die(3) function.
113 explain_message_mknod
115 void explain_message_mknod(char *message, int message_size, const char
116 *pathname, mode_t mode, dev_t dev);
117 The explain_message_mknod function is used to obtain an explanation of
119 an error returned by the mknod(2) system call. The least the message
120 will contain is the value of strerror(errno), but usually it will do
121 much better, and indicate the underlying cause in more detail.
122 The errno global variable will be used to obtain the error value to be
124 decoded.
125 message The location in which to store the returned message. If a suit‐
127 able message return buffer is supplied, this function is thread
128 safe.
129 message_size
131 The size in bytes of the location in which to store the
132 returned message.
133 pathname
135 The original pathname, exactly as passed to the mknod(2) system
136 call.
137 mode The original mode, exactly as passed to the mknod(2) system
139 call.
140 dev The original dev, exactly as passed to the mknod(2) system
142 call.
143 Example: This function is intended to be used in a fashion similar to
145 the following example:
146 if (mknod(pathname, mode, dev) < 0)
147 {
148 char message[3000];
149 explain_message_mknod(message, sizeof(message), pathname,
150 mode, dev);
151 fprintf(stderr, "%s\n", message);
152 exit(EXIT_FAILURE);
153 }
154 The above code example is available pre‐packaged as the
156 explain_mknod_or_die(3) function.
157 explain_message_errno_mknod
159 void explain_message_errno_mknod(char *message, int message_size, int
160 errnum, const char *pathname, mode_t mode, dev_t dev);
161 The explain_message_errno_mknod function is used to obtain an explana‐
163 tion of an error returned by the mknod(2) system call. The least the
164 message will contain is the value of strerror(errno), but usually it
165 will do much better, and indicate the underlying cause in more detail.
166 message The location in which to store the returned message. If a suit‐
168 able message return buffer is supplied, this function is thread
169 safe.
170 message_size
172 The size in bytes of the location in which to store the
173 returned message.
174 errnum The error value to be decoded, usually obtained from the errno
176 global variable just before this function is called. This is
177 necessary if you need to call any code between the system call
178 to be explained and this function, because many libc functions
179 will alter the value of errno.
180 pathname
182 The original pathname, exactly as passed to the mknod(2) system
183 call.
184 mode The original mode, exactly as passed to the mknod(2) system
186 call.
187 dev The original dev, exactly as passed to the mknod(2) system
189 call.
190 Example: This function is intended to be used in a fashion similar to
192 the following example:
193 if (mknod(pathname, mode, dev) < 0)
194 {
195 int err = errno;
196 char message[3000];
197 explain_message_errno_mknod(message, sizeof(message), err,
198 pathname, mode, dev);
199 fprintf(stderr, "%s\n", message);
200 exit(EXIT_FAILURE);
201 }
202 The above code example is available pre‐packaged as the
204 explain_mknod_or_die(3) function.
205
207 mknod(2)
208 create a special or ordinary file
209 explain_mknod_or_die(3)
211 create a special or ordinary file and report errors
212
214 libexplain version 1.4
215 Copyright (C) 2009 Peter Miller
216 explain_mknod(3)