1explain_getpeername(3) Library Functions Manual explain_getpeername(3)
2
6 explain_getpeername - explain getpeername(2) errors
7
9 #include <libexplain/getpeername.h>
10 const char *explain_getpeername(int fildes, struct sockaddr *sock_addr,
11 socklen_t *sock_addr_size);
12 const char *explain_errno_getpeername(int errnum, int fildes, struct
13 sockaddr *sock_addr, socklen_t *sock_addr_size);
14 void explain_message_getpeername(char *message, int message_size, int
15 fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size);
16 void explain_message_errno_getpeername(char *message, int message_size,
17 int errnum, int fildes, struct sockaddr *sock_addr, socklen_t
18 *sock_addr_size);
19
21 These functions may be used to obtain explanations for errors returned
22 by the getpeername(2) system call.
23 explain_getpeername
25 const char *explain_getpeername(int fildes, struct sockaddr *sock_addr,
26 socklen_t *sock_addr_size);
27 The explain_getpeername function is used to obtain an explanation of an
29 error returned by the getpeername(2) system call. The least the mes‐
30 sage will contain is the value of strerror(errno), but usually it will
31 do much better, and indicate the underlying cause in more detail.
32 The errno global variable will be used to obtain the error value to be
34 decoded.
35 This function is intended to be used in a fashion similar to the fol‐
37 lowing example:
38 struct sockaddr sock_addr;
39 socklen_t sock_addr_len = sizeof(sock_addr);
40 if (getpeername(fildes, &sock_addr, &sock_addr_size) < 0)
41 {
42 fprintf(stderr, "%s\n", explain_getpeername(fildes,
43 &sock_addr, &sock_addr_size));
44 exit(EXIT_FAILURE);
45 }
46 The above code example is available pre‐packaged as the explain_get‐
48 peername_or_die(3) function.
49 fildes The original fildes, exactly as passed to the getpeername(2)
51 system call.
52 sock_addr
54 The original sock_addr, exactly as passed to the getpeername(2)
55 system call.
56 sock_addr_size
58 The original sock_addr_size, exactly as passed to the getpeer‐
59 name(2) system call.
60 Returns:
62 The message explaining the error. This message buffer is
63 shared by all libexplain functions which do not supply a buffer
64 in their argument list. This will be overwritten by the next
65 call to any libexplain function which shares this buffer,
66 including other threads.
67 Note: This function is not thread safe, because it shares a return buf‐
69 fer across all threads, and many other functions in this library.
70 explain_errno_getpeername
72 const char *explain_errno_getpeername(int errnum, int fildes, struct
73 sockaddr *sock_addr, socklen_t *sock_addr_size);
74 The explain_errno_getpeername function is used to obtain an explanation
76 of an error returned by the getpeername(2) system call. The least the
77 message will contain is the value of strerror(errnum), but usually it
78 will do much better, and indicate the underlying cause in more detail.
79 This function is intended to be used in a fashion similar to the fol‐
81 lowing example:
82 struct sockaddr sock_addr;
83 socklen_t sock_addr_len = sizeof(sock_addr);
84 if (getpeername(fildes, &sock_addr, &sock_addr_size) < 0)
85 {
86 int err = errno;
87 fprintf(stderr, "%s\n", explain_errno_getpeername(err,
88 fildes, &sock_addr, &sock_addr_size));
89 exit(EXIT_FAILURE);
90 }
91 The above code example is available pre‐packaged as the explain_get‐
93 peername_or_die(3) function.
94 errnum The error value to be decoded, usually obtained from the errno
96 global variable just before this function is called. This is
97 necessary if you need to call any code between the system call
98 to be explained and this function, because many libc functions
99 will alter the value of errno.
100 fildes The original fildes, exactly as passed to the getpeername(2)
102 system call.
103 sock_addr
105 The original sock_addr, exactly as passed to the getpeername(2)
106 system call.
107 sock_addr_size
109 The original sock_addr_size, exactly as passed to the getpeer‐
110 name(2) system call.
111 Returns:
113 The message explaining the error. This message buffer is
114 shared by all libexplain functions which do not supply a buffer
115 in their argument list. This will be overwritten by the next
116 call to any libexplain function which shares this buffer,
117 including other threads.
118 Note: This function is not thread safe, because it shares a return buf‐
120 fer across all threads, and many other functions in this library.
121 explain_message_getpeername
123 void explain_message_getpeername(char *message, int message_size, int
124 fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size);
125 The explain_message_getpeername function may be used to obtain an
127 explanation of an error returned by the getpeername(2) system call.
128 The least the message will contain is the value of strerror(errno), but
129 usually it will do much better, and indicate the underlying cause in
130 more detail.
131 The errno global variable will be used to obtain the error value to be
133 decoded.
134 This function is intended to be used in a fashion similar to the fol‐
136 lowing example:
137 struct sockaddr sock_addr;
138 socklen_t sock_addr_len = sizeof(sock_addr);
139 if (getpeername(fildes, &sock_addr, &sock_addr_size) < 0)
140 {
141 char message[3000];
142 explain_message_getpeername(message, sizeof(message),
143 fildes, &sock_addr, &sock_addr_size);
144 fprintf(stderr, "%s\n", message);
145 exit(EXIT_FAILURE);
146 }
147 The above code example is available pre‐packaged as the explain_get‐
149 peername_or_die(3) function.
150 message The location in which to store the returned message. If a
152 suitable message return buffer is supplied, this function is
153 thread safe.
154 message_size
156 The size in bytes of the location in which to store the
157 returned message.
158 fildes The original fildes, exactly as passed to the getpeername(2)
160 system call.
161 sock_addr
163 The original sock_addr, exactly as passed to the getpeername(2)
164 system call.
165 sock_addr_size
167 The original sock_addr_size, exactly as passed to the getpeer‐
168 name(2) system call.
169 explain_message_errno_getpeername
171 void explain_message_errno_getpeername(char *message, int message_size,
172 int errnum, int fildes, struct sockaddr *sock_addr, socklen_t
173 *sock_addr_size);
174 The explain_message_errno_getpeername function may be used to obtain an
176 explanation of an error returned by the getpeername(2) system call.
177 The least the message will contain is the value of strerror(errnum),
178 but usually it will do much better, and indicate the underlying cause
179 in more detail.
180 This function is intended to be used in a fashion similar to the fol‐
182 lowing example:
183 struct sockaddr sock_addr;
184 socklen_t sock_addr_len = sizeof(sock_addr);
185 if (getpeername(fildes, &sock_addr, &sock_addr_size) < 0)
186 {
187 int err = errno;
188 char message[3000];
189 explain_message_errno_getpeername(message, sizeof(message),
190 err, fildes, &sock_addr, &sock_addr_size);
191 fprintf(stderr, "%s\n", message);
192 exit(EXIT_FAILURE);
193 }
194 The above code example is available pre‐packaged as the explain_get‐
196 peername_or_die(3) function.
197 message The location in which to store the returned message. If a
199 suitable message return buffer is supplied, this function is
200 thread safe.
201 message_size
203 The size in bytes of the location in which to store the
204 returned message.
205 errnum The error value to be decoded, usually obtained from the errno
207 global variable just before this function is called. This is
208 necessary if you need to call any code between the system call
209 to be explained and this function, because many libc functions
210 will alter the value of errno.
211 fildes The original fildes, exactly as passed to the getpeername(2)
213 system call.
214 sock_addr
216 The original sock_addr, exactly as passed to the getpeername(2)
217 system call.
218 sock_addr_size
220 The original sock_addr_size, exactly as passed to the getpeer‐
221 name(2) system call.
222
224 getpeername(2)
225 get name of connected peer socket
226 explain_getpeername_or_die(3)
228 get name of connected peer socket and report errors
229
231 libexplain version 0.40
232 Copyright (C) 2009 Peter Miller
233 explain_getpeername(3)