1 .\" Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
2 .\" Copyright (C) 2000, 2001, 2003 Internet Software Consortium.
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20 .\" Title: lwres_getaddrinfo
22 .\" Generator: DocBook XSL Stylesheets v1.71.1 <http://docbook.sf.net/>
23 .\" Date: Jun 30, 2000
27 .TH "LWRES_GETADDRINFO" "3" "Jun 30, 2000" "BIND9" "BIND9"
28 .\" disable hyphenation
30 .\" disable justification (adjust text to left margin only)
33 lwres_getaddrinfo, lwres_freeaddrinfo \- socket address structure to host and service name
36 #include <lwres/netdb.h>
39 .BI "int lwres_getaddrinfo(const\ char\ *" "hostname" ", const\ char\ *" "servname" ", const\ struct\ addrinfo\ *" "hints" ", struct\ addrinfo\ **" "res" ");"
41 .BI "void lwres_freeaddrinfo(struct\ addrinfo\ *" "ai" ");"
43 If the operating system does not provide a
44 \fBstruct addrinfo\fR, the following structure is used:
49 int ai_flags; /* AI_PASSIVE, AI_CANONNAME */
50 int ai_family; /* PF_xxx */
51 int ai_socktype; /* SOCK_xxx */
52 int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
53 size_t ai_addrlen; /* length of ai_addr */
54 char *ai_canonname; /* canonical name for hostname */
55 struct sockaddr *ai_addr; /* binary address */
56 struct addrinfo *ai_next; /* next structure in linked list */
63 \fBlwres_getaddrinfo()\fR
64 is used to get a list of IP addresses and port numbers for host
67 \fIservname\fR. The function is the lightweight resolver's implementation of
69 as defined in RFC2133.
73 are pointers to null\-terminated strings or
76 is either a host name or a numeric host address string: a dotted decimal IPv4 address or an IPv6 address.
78 is either a decimal port number or a service name as listed in
82 is an optional pointer to a
83 \fBstruct addrinfo\fR. This structure can be used to provide hints concerning the type of socket that the caller supports or wishes to use. The caller can supply the following structure elements in
88 The protocol family that should be used. When
91 \fBPF_UNSPEC\fR, it means the caller will accept any protocol family supported by the operating system.
96 denotes the type of socket \(em
101 \(em that is wanted. When
103 is zero the caller will accept any socket type.
108 indicates which transport protocol is wanted: IPPROTO_UDP or IPPROTO_TCP. If
110 is zero the caller will accept any protocol.
117 bit is set, a successful call to
118 \fBlwres_getaddrinfo()\fR
119 will return a null\-terminated string containing the canonical name of the specified hostname in
123 structure returned. Setting the
125 bit indicates that the returned socket address structure is intended for used in a call to
126 \fBbind\fR(2). In this case, if the hostname argument is a
128 pointer, then the IP address portion of the socket address structure will be set to
130 for an IPv4 address or
131 \fBIN6ADDR_ANY_INIT\fR
138 bit, the returned socket address structure will be ready for use in a call to
140 for a connection\-oriented protocol or
144 if a connectionless protocol was chosen. The IP address portion of the socket address structure will be set to the loopback address if
159 should be treated as a numeric string defining an IPv4 or IPv6 address and no name resolution should be attempted.
162 All other elements of the
163 \fBstruct addrinfo\fR
172 is treated as if the caller provided a
173 \fBstruct addrinfo\fR
174 initialized to zero with
175 \fBai_family\fRset to
178 After a successful call to
179 \fBlwres_getaddrinfo()\fR,
181 is a pointer to a linked list of one or more
184 \fBstruct addrinfo\fR
185 in this list cn be processed by following the
189 pointer is encountered. The three members
191 \fBai_socktype\fR, and
195 structure contain the corresponding arguments for a call to
196 \fBsocket\fR(2). For each
198 structure in the list, the
200 member points to a filled\-in socket address structure of length
203 All of the information returned by
204 \fBlwres_getaddrinfo()\fR
205 is dynamically allocated: the addrinfo structures, and the socket address structures and canonical host name strings pointed to by the
206 \fBaddrinfo\fRstructures. Memory allocated for the dynamically allocated structures created by a successful call to
207 \fBlwres_getaddrinfo()\fR
209 \fBlwres_freeaddrinfo()\fR.
212 \fBstruct addrinfo\fR
214 \fBlwres_getaddrinfo()\fR.
217 \fBlwres_getaddrinfo()\fR
218 returns zero on success or one of the error codes listed in
219 \fBgai_strerror\fR(3)
220 if an error occurs. If both
226 \fBlwres_getaddrinfo()\fR
232 \fBlwres_getaddrinfo\fR(3),
233 \fBlwres_freeaddrinfo\fR(3),
234 \fBlwres_gai_strerror\fR(3),
236 \fBgetservbyname\fR(3),
243 Copyright \(co 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
245 Copyright \(co 2000, 2001, 2003 Internet Software Consortium.