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2 .\" Copyright (C) 2000, 2001, 2003 Internet Software Consortium.
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16 .\" $Id: lwres_context.3,v 1.28.418.1 2009/07/11 01:55:21 tbox Exp $
20 .\" Title: lwres_context
22 .\" Generator: DocBook XSL Stylesheets v1.71.1 <http://docbook.sf.net/>
23 .\" Date: Jun 30, 2000
27 .TH "LWRES_CONTEXT" "3" "Jun 30, 2000" "BIND9" "BIND9"
28 .\" disable hyphenation
30 .\" disable justification (adjust text to left margin only)
33 lwres_context_create, lwres_context_destroy, lwres_context_nextserial, lwres_context_initserial, lwres_context_freemem, lwres_context_allocmem, lwres_context_sendrecv \- lightweight resolver context management
36 #include <lwres/lwres.h>
39 .BI "lwres_result_t lwres_context_create(lwres_context_t\ **" "contextp" ", void\ *" "arg" ", lwres_malloc_t\ " "malloc_function" ", lwres_free_t\ " "free_function" ");"
41 .BI "lwres_result_t lwres_context_destroy(lwres_context_t\ **" "contextp" ");"
43 .BI "void lwres_context_initserial(lwres_context_t\ *" "ctx" ", lwres_uint32_t\ " "serial" ");"
45 .BI "lwres_uint32_t lwres_context_nextserial(lwres_context_t\ *" "ctx" ");"
47 .BI "void lwres_context_freemem(lwres_context_t\ *" "ctx" ", void\ *" "mem" ", size_t\ " "len" ");"
49 .BI "void lwres_context_allocmem(lwres_context_t\ *" "ctx" ", size_t\ " "len" ");"
51 .BI "void * lwres_context_sendrecv(lwres_context_t\ *" "ctx" ", void\ *" "sendbase" ", int\ " "sendlen" ", void\ *" "recvbase" ", int\ " "recvlen" ", int\ *" "recvd_len" ");"
54 \fBlwres_context_create()\fR
57 structure for use in lightweight resolver operations. It holds a socket and other data needed for communicating with a resolver daemon. The new
60 \fIcontextp\fR, a pointer to a
64 pointer must initially be NULL, and is modified to point to the newly created
65 \fBlwres_context_t\fR.
67 When the lightweight resolver needs to perform dynamic memory allocation, it will call
69 to allocate memory and
75 are NULL, memory is allocated using
77 \fBfree\fR(3). It is not permitted to have a NULL
83 is passed as the first parameter to the memory allocation functions. If
89 is unused and should be passed as NULL.
91 Once memory for the structure has been allocated, it is initialized using
92 \fBlwres_conf_init\fR(3)
96 \fBlwres_context_destroy()\fR
98 \fBlwres_context_t\fR, closing its socket.
100 is a pointer to a pointer to the context that is to be destroyed. The pointer will be set to NULL when the context has been destroyed.
102 The context holds a serial number that is used to identify resolver request packets and associate responses with the corresponding requests. This serial number is controlled using
103 \fBlwres_context_initserial()\fR
105 \fBlwres_context_nextserial()\fR.
106 \fBlwres_context_initserial()\fR
107 sets the serial number for context
111 \fBlwres_context_nextserial()\fR
112 increments the serial number and returns the previous value.
114 Memory for a lightweight resolver context is allocated and freed using
115 \fBlwres_context_allocmem()\fR
117 \fBlwres_context_freemem()\fR. These use whatever allocations were defined when the context was created with
118 \fBlwres_context_create()\fR.
119 \fBlwres_context_allocmem()\fR
122 bytes of memory and if successful returns a pointer to the allocated storage.
123 \fBlwres_context_freemem()\fR
126 bytes of space starting at location
129 \fBlwres_context_sendrecv()\fR
130 performs I/O for the context
131 \fIctx\fR. Data are read and written from the context's socket. It writes data from
133 \(em typically a lightweight resolver query packet \(em and waits for a reply which is copied to the receive buffer at
134 \fIrecvbase\fR. The number of bytes that were written to this receive buffer is returned in
138 \fBlwres_context_create()\fR
140 \fBLWRES_R_NOMEMORY\fR
142 \fBstruct lwres_context\fR
143 could not be allocated,
144 \fBLWRES_R_SUCCESS\fR
147 Successful calls to the memory allocator
148 \fBlwres_context_allocmem()\fR
149 return a pointer to the start of the allocated space. It returns NULL if memory could not be allocated.
151 \fBLWRES_R_SUCCESS\fR
153 \fBlwres_context_sendrecv()\fR
154 completes successfully.
155 \fBLWRES_R_IOERROR\fR
156 is returned if an I/O error occurs and
157 \fBLWRES_R_TIMEOUT\fR
159 \fBlwres_context_sendrecv()\fR
160 times out waiting for a response.
163 \fBlwres_conf_init\fR(3),
167 Copyright \(co 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
169 Copyright \(co 2000, 2001, 2003 Internet Software Consortium.