1explain_unlink(3) Library Functions Manual explain_unlink(3)
2
6 explain_unlink - explain unlink(2) errors
7
9 #include <libexplain/unlink.h>
10 const char *explain_unlink(const char *pathname);
11 void explain_message_unlink(char *message, int message_size, const char
12 *pathname);
13 const char *explain_errno_unlink(int errnum, const char *pathname);
14 void explain_message_errno_unlink(char *message, int message_size, int
15 errnum, const char *pathname);
16
18 These functions may be used to obtain explanations for unlink(2)
19 errors.
20 explain_unlink
22 const char *explain_unlink(const char *pathname);
23 The explain_unlink function is used to obtain an explanation of an
25 error returned by the unlink(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 The errno global variable will be used to obtain the error value to be
30 decoded.
31 This function is intended to be used in a fashion similar to the fol‐
33 lowing example:
34 if (unlink(pathname) < 0)
35 {
36 fprintf(stderr, '%s0, explain_unlink(pathname));
37 exit(EXIT_FAILURE);
38 }
39 pathname
41 The original pathname, exactly as passed to the unlink(2) sys‐
42 tem call.
43 Returns:
45 The message explaining the error. This message buffer is
46 shared by all libexplain functions which do not supply a buffer
47 in their argument list. This will be overwritten by the next
48 call to any libexplain function which shares this buffer,
49 including other threads.
50 Note: This function is not thread safe, because it shares a return buf‐
52 fer across all threads, and many other functions in this library.
53 explain_errno_unlink
55 const char *explain_errno_unlink(int errnum, const char * pathname);
56 The explain_errno_unlink function is used to obtain an explanation of
58 an error returned by the unlink(2) system call. The least the message
59 will contain is the value of strerror(errnum), but usually it will do
60 much better, and indicate the underlying cause in more detail.
61 This function is intended to be used in a fashion similar to the fol‐
63 lowing example:
64 if (unlink(pathname) < 0)
65 {
66 int err = errno;
67 fprintf(stderr, '%s0, explain_errno_unlink(err, pathname));
68 exit(EXIT_FAILURE);
69 }
70 errnum The error value to be decoded, usually obtained from the errno
72 global variable just before this function is called. This is
73 necessary if you need to call any code between the system call
74 to be explained and this function, because many libc functions
75 will alter the value of errno.
76 pathname
78 The original pathname, exactly as passed to the unlink(2) sys‐
79 tem call.
80 Returns:
82 The message explaining the error. This message buffer is
83 shared by all libexplain functions which do not supply a buffer
84 in their argument list. This will be overwritten by the next
85 call to any libexplain function which shares this buffer,
86 including other threads.
87 Note: This function is not thread safe, because it shares a return buf‐
89 fer across all threads, and many other functions in this library.
90 explain_message_unlink
92 void explain_message_unlink(char *message, int message_size, const char
93 *pathname);
94 The explain_message_unlink function is used to obtain an explanation of
96 an error returned by the unlink(2) system call. The least the message
97 will contain is the value of strerror(errno), but usually it will do
98 much better, and indicate the underlying cause in more detail.
99 The errno global variable will be used to obtain the error value to be
101 decoded.
102 This function is intended to be used in a fashion similar to the fol‐
104 lowing example:
105 if (unlink(pathname) < 0)
106 {
107 char message[3000];
108 explain_message_unlink(message, sizeof(message), pathname);
109 fprintf(stderr, '%s0, message);
110 exit(EXIT_FAILURE);
111 }
112 message The location in which to store the returned message. Because a
114 message return buffer has been supplied, this function is
115 thread safe.
116 message_size
118 The size in bytes of the location in which to store the
119 returned message.
120 pathname
122 The original pathname, exactly as passed to the unlink(2) sys‐
123 tem call.
124 explain_message_errno_unlink
126 void explain_message_errno_unlink(char *message, int message_size, int
127 errnum, const char *pathname);
128 The explain_message_errno_unlink function is used to obtain an explana‐
130 tion of an error returned by the unlink(2) system call. The least the
131 message will contain is the value of strerror(errnum), but usually it
132 will do much better, and indicate the underlying cause in more detail.
133 This function is intended to be used in a fashion similar to the fol‐
135 lowing example:
136 if (unlink(pathname) < 0)
137 {
138 int err = errno;
139 char message[3000];
140 explain_message_errno_unlink(message, sizeof(message), err,
141 pathname);
142 fprintf(stderr, '%s0, message);
143 exit(EXIT_FAILURE);
144 }
145 message The location in which to store the returned message. Because a
147 message return buffer has been supplied, this function is
148 thread safe.
149 message_size
151 The size in bytes of the location in which to store the
152 returned message.
153 errnum The error value to be decoded, usually obtained from the errno
155 global variable just before this function is called. This is
156 necessary if you need to call any code between the system call
157 to be explained and this function, because many libc functions
158 will alter the value of errno.
159 pathname
161 The original pathname, exactly as passed to the unlink(2) sys‐
162 tem call.
163
165 libexplain version 1.4
166 Copyright (C) 2008 Peter Miller
167
169 Written by Peter Miller <pmiller@opensource.org.au>
170 explain_unlink(3)