1explain_accept4(3) Library Functions Manual explain_accept4(3)
2
6 explain_accept4 - explain accept4(2) errors
7
9 #include <libexplain/accept4.h>
10 const char *explain_accept4(int fildes, struct sockaddr *sock_addr,
11 socklen_t *sock_addr_size, int flags);
12 const char *explain_errno_accept4(int errnum, int fildes, struct sock‐
13 addr *sock_addr, socklen_t *sock_addr_size, int flags);
14 void explain_message_accept4(char *message, int message_size, int
15 fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size, int
16 flags);
17 void explain_message_errno_accept4(char *message, int message_size, int
18 errnum, int fildes, struct sockaddr *sock_addr, socklen_t
19 *sock_addr_size, int flags);
20
22 These functions may be used to obtain explanations for errors returned
23 by the accept4(2) system call.
24 explain_accept4
26 const char *explain_accept4(int fildes, struct sockaddr *sock_addr,
27 socklen_t *sock_addr_size, int flags);
28 The explain_accept4 function is used to obtain an explanation of an
30 error returned by the accept4(2) system call. The least the message
31 will contain is the value of strerror(errno), but usually it will do
32 much better, and indicate the underlying cause in more detail.
33 The errno global variable will be used to obtain the error value to be
35 decoded.
36 fildes The original fildes, exactly as passed to the accept4(2) system
38 call.
39 sock_addr
41 The original sock_addr, exactly as passed to the accept4(2)
42 system call.
43 sock_addr_size
45 The original sock_addr_size, exactly as passed to the
46 accept4(2) system call.
47 flags The original flags, exactly as passed to the accept4(2) system
49 call.
50 Returns:
52 The message explaining the error. This message buffer is shared
53 by all libexplain functions which do not supply a buffer in
54 their argument list. This will be overwritten by the next call
55 to any libexplain function which shares this buffer, including
56 other threads.
57 Note: This function is not thread safe, because it shares a return buf‐
59 fer across all threads, and many other functions in this library.
60 Example: This function is intended to be used in a fashion similar to
62 the following example:
63 int result = accept4(fildes, sock_addr, sock_addr_size, flags);
64 if (result < 0)
65 {
66 fprintf(stderr, "%s\n", explain_accept4(fildes, sock_addr,
67 sock_addr_size, flags));
68 exit(EXIT_FAILURE);
69 }
70 The above code example is available pre‐packaged as the
72 explain_accept4_or_die(3) function.
73 explain_errno_accept4
75 const char *explain_errno_accept4(int errnum, int fildes, struct sock‐
76 addr *sock_addr, socklen_t *sock_addr_size, int flags);
77 The explain_errno_accept4 function is used to obtain an explanation of
79 an error returned by the accept4(2) system call. The least the message
80 will contain is the value of strerror(errno), but usually it will do
81 much better, and indicate the underlying cause in more detail.
82 errnum The error value to be decoded, usually obtained from the errno
84 global variable just before this function is called. This is
85 necessary if you need to call any code between the system call
86 to be explained and this function, because many libc functions
87 will alter the value of errno.
88 fildes The original fildes, exactly as passed to the accept4(2) system
90 call.
91 sock_addr
93 The original sock_addr, exactly as passed to the accept4(2)
94 system call.
95 sock_addr_size
97 The original sock_addr_size, exactly as passed to the
98 accept4(2) system call.
99 flags The original flags, exactly as passed to the accept4(2) system
101 call.
102 Returns:
104 The message explaining the error. This message buffer is shared
105 by all libexplain functions which do not supply a buffer in
106 their argument list. This will be overwritten by the next call
107 to any libexplain function which shares this buffer, including
108 other threads.
109 Note: This function is not thread safe, because it shares a return buf‐
111 fer across all threads, and many other functions in this library.
112 Example: This function is intended to be used in a fashion similar to
114 the following example:
115 int result = accept4(fildes, sock_addr, sock_addr_size, flags);
116 if (result < 0)
117 {
118 int err = errno;
119 fprintf(stderr, "%s\n", explain_errno_accept4(err, fildes,
120 sock_addr, sock_addr_size, flags));
121 exit(EXIT_FAILURE);
122 }
123 The above code example is available pre‐packaged as the
125 explain_accept4_or_die(3) function.
126 explain_message_accept4
128 void explain_message_accept4(char *message, int message_size, int
129 fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size, int
130 flags);
131 The explain_message_accept4 function is used to obtain an explanation
133 of an error returned by the accept4(2) system call. The least the mes‐
134 sage will contain is the value of strerror(errno), but usually it will
135 do much better, and indicate the underlying cause in more detail.
136 The errno global variable will be used to obtain the error value to be
138 decoded.
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 fildes The original fildes, exactly as passed to the accept4(2) system
149 call.
150 sock_addr
152 The original sock_addr, exactly as passed to the accept4(2)
153 system call.
154 sock_addr_size
156 The original sock_addr_size, exactly as passed to the
157 accept4(2) system call.
158 flags The original flags, exactly as passed to the accept4(2) system
160 call.
161 Example: This function is intended to be used in a fashion similar to
163 the following example:
164 int result = accept4(fildes, sock_addr, sock_addr_size, flags);
165 if (result < 0)
166 {
167 char message[3000];
168 explain_message_accept4(message, sizeof(message), fildes,
169 sock_addr, sock_addr_size, flags);
170 fprintf(stderr, "%s\n", message);
171 exit(EXIT_FAILURE);
172 }
173 The above code example is available pre‐packaged as the
175 explain_accept4_or_die(3) function.
176 explain_message_errno_accept4
178 void explain_message_errno_accept4(char *message, int message_size, int
179 errnum, int fildes, struct sockaddr *sock_addr, socklen_t
180 *sock_addr_size, int flags);
181 The explain_message_errno_accept4 function is used to obtain an expla‐
183 nation of an error returned by the accept4(2) system call. The least
184 the message will contain is the value of strerror(errno), but usually
185 it will do much better, and indicate the underlying cause in more
186 detail.
187 message The location in which to store the returned message. If a suit‐
189 able message return buffer is supplied, this function is thread
190 safe.
191 message_size
193 The size in bytes of the location in which to store the
194 returned message.
195 errnum The error value to be decoded, usually obtained from the errno
197 global variable just before this function is called. This is
198 necessary if you need to call any code between the system call
199 to be explained and this function, because many libc functions
200 will alter the value of errno.
201 fildes The original fildes, exactly as passed to the accept4(2) system
203 call.
204 sock_addr
206 The original sock_addr, exactly as passed to the accept4(2)
207 system call.
208 sock_addr_size
210 The original sock_addr_size, exactly as passed to the
211 accept4(2) system call.
212 flags The original flags, exactly as passed to the accept4(2) system
214 call.
215 Example: This function is intended to be used in a fashion similar to
217 the following example:
218 int result = accept4(fildes, sock_addr, sock_addr_size, flags);
219 if (result < 0)
220 {
221 int err = errno;
222 char message[3000];
223 explain_message_errno_accept4(message, sizeof(message), err,
224 fildes, sock_addr, sock_addr_size, flags);
225 fprintf(stderr, "%s\n", message);
226 exit(EXIT_FAILURE);
227 }
228 The above code example is available pre‐packaged as the
230 explain_accept4_or_die(3) function.
231
233 accept4(2)
234 accept a connection on a socket
235 explain_accept4_or_die(3)
237 accept a connection on a socket and report errors
238
240 libexplain version 1.4
241 Copyright (C) 2009 Peter Miller
242 explain_accept4(3)