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1 perry 1 getipnodebyname
2 !!!getipnodebyname
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 RETURN VALUE
7 SEE ALSO
8 ----
9 !!NAME
10
11
12 getipnodebyname, getipnodebyaddr, freehostent - get network host names and addresses
13 !!SYNOPSIS
14
15
16 __#include
17 __''name''__,
18 int__ ''af''__, int__ ''flags''__,
19 int *__''error_num''__);
20 struct hostent *getipnodebyaddr(const void *__''addr''__,
21 size_t__ ''len''__, int__ ''af''__,
22 int *__''error_num''__);
23 void freehostent(struct hostent *__''ip''__);
24 __
25 !!DESCRIPTION
26
27
28 The getipnodebyname(3) and getipnodebyaddr(3)
29 functions return the names and addresses of a network host.
30 These functions return a pointer to the following
31 structure:
32
33
34 __struct hostent {
35 char *__''h_name''__;
36 char **__''h_aliases''__;
37 int__ '' h_addrtype''__;
38 int__ '' h_length''__;
39 char **__''h_addr_list''__;
40 };
41 __These functions replace the gethostbyname(3) and gethostbyaddr(3) functions, which could only access the IPv4 network address family. The getipnodebyname(3) and getipnodebyaddr(3) functions can access multiple network address families.
42
43
44 Unlike the __gethostby__ functions, these functions
45 return pointers to dynamically allocated memory. The
46 freehostent(3) function is used to release the
47 dynamically allocated memory after the caller no longer
48 needs the __hostent__ structure.
49
50
51 __getipnodebyname parameters__
52
53
54 The getipnodebyname(3) function looks up network
55 addresses for the host specified by the ''name''
56 parameter. The ''af'' parameter specifies one of the
57 following values:
58
59
60 __AF_INET__
61
62
63 The ''name'' parameter points to a dotted-quad IPv4
64 address or a name of an IPv4 network host.
65
66
67 __AF_INET6__
68
69
70 The ''name'' parameter points to a hexadecimal IPv6
71 address or a name of an IPv6 network host.
72
73
74 The ''flags'' parameter specifies additional options.
75 More than one option can be specified by logically OR-ing
76 them together. ''flags'' should be set to 0 if no options
77 are desired.
78
79
80 __AI_V4MAPPED__
81
82
83 This flag is used with __AF_INET6__ to request a query
84 for IPv4 addresses instead of IPv6 addresses; the IPv4
85 addresses will be mapped to IPv6 addresses.
86
87
88 __AI_ALL__
89
90
91 This flag is used with __AI_V4MAPPED__ to request a query
92 for both IPv4 and IPv6 addresses. Any IPv4 address found
93 will be mapped to an IPv6 address.
94
95
96 __AI_ADDRCONFIG__
97
98
99 This flag is used with __AF_INET6__ to further request
100 that queries for IPv6 addresses should not be made unless
101 the system has at least one IPv6 address assigned to a
102 network interface, and that queries for IPv4 addresses
103 should not be made unless the system has at least one IPv4
104 address assigned to a network interface. This flag may be
105 used by itself or with the __AI_V4MAPPED__
106 flag.
107
108
109 __AI_ALL__
110
111
112 This flag is equivalent to __(AI_ADDRCONFIG |
113 AI_V4MAPPED)__.
114
115
116 __getipnodebyaddr parameters__
117
118
119 The getipnodebyaddr(3) function looks up the name of
120 the host whose network address is specified by the
121 ''addr'' parameter. The ''af'' parameter specifies one
122 of the following values:
123
124
125 __AF_INET__
126
127
128 The ''addr'' parameter points to a __struct in_addr__
129 and ''len'' must be set to __sizeof(struct
130 in_addr)__.
131
132
133 __AF_INET6__
134
135
136 The ''addr'' parameter points to a __struct in6_addr__
137 and ''len'' must be set to __sizeof(struct
138 in6_addr)__.
139 !!RETURN VALUE
140
141
142 A null pointer is returned if an error occurred, and
143 ''error_num'' will contain an error code from the
144 following list:
145
146
147 __HOST_NOT_FOUND__
148
149
150 The host name or network address was not found.
151
152
153 __NO_ADDRESS__
154
155
156 The domain name server recognized the network address or
157 name, but no answer was returned. This can happen if the
158 network host has only IPv4 addresses and a request has been
159 made for IPv6 information only, or vice versa.
160
161
162 __NO_RECOVERY__
163
164
165 The domain name server returned a permanent failure
166 response.
167
168
169 __TRY_AGAIN__
170
171
172 The domain name server returned a temporary failure
173 response. You might have better luck next time.
174
175
176 A successful query returns a pointer to a __hostent__
177 structure that contains the following fields:
178
179
180 __h_name__
181
182
183 This is the official name of this network host.
184
185
186 __h_aliases__
187
188
189 This is an array of pointers to unofficial aliases for the
190 same host. The array is terminated by a null
191 pointer.
192
193
194 __h_addrtype__
195
196
197 This is a copy of the ''af'' parameter to
198 getipnodebyname(3) or getipnodebyaddr(3).
199 ''h_addrtype'' will always be __AF_INET__ if the
200 ''af'' parameter was __AF_INET__. ''h_addrtype''
201 will always be __AF_INET6__ if the ''af'' parameter
202 was __AF_INET6__.
203
204
205 __h_length__
206
207
208 This field will be set to __sizeof(struct in_addr)__ if
209 ''h_addrtype'' is AF_INET, and to __sizeof(struct
210 in6_addr)__ if ''h_addrtype'' is AF_INET6.
211
212
213 __h_addr_list__
214
215
216 This is an array of one or more pointers to network address
217 structures for the network host. The array is terminated by
218 a null pointer.
219 !!SEE ALSO
220
221
4 perry 222 getaddrinfo(3), inet_ntop(3),
223 inet_pton(3)
1 perry 224 ----
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