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.\" Copyright 1998 by the Massachusetts Institute of Technology.
.\" Permission to use, copy, modify, and distribute this
.\" software and its documentation for any purpose and without
.\" fee is hereby granted, provided that the above copyright
.\" notice appear in all copies and that both that copyright
.\" notice and this permission notice appear in supporting
.\" documentation, and that the name of M.I.T. not be used in
.\" advertising or publicity pertaining to distribution of the
.\" software without specific, written prior permission.
.\" M.I.T. makes no representations about the suitability of
.\" this software for any purpose. It is provided "as is"
.\" without express or implied warranty.
.TH ARES_CREATE_QUERY 3 "17 Aug 2012"
ares_create_query \- Compose a single-question DNS query buffer
#include <ares.h>
int ares_create_query(const char *\fIname\fP,
int \fIdnsclass\fP,
int \fItype\fP,
unsigned short \fIid\fP,
int \fIrd\fP,
unsigned char **\fIbuf\fP,
int *\fIbuflen\fP,
int \fImax_udp_size\fP)
The \fIares_create_query(3)\fP function composes a DNS query with a single
question. The parameter \fIname\fP gives the query name as a NUL-terminated C
string of period-separated labels optionally ending with a period; periods and
backslashes within a label must be escaped with a backlash.
The parameters \fIdnsclass\fP and \fItype\fP give the class and type of the
query using the values defined in \fB<arpa/nameser.h>\fP.
The parameter \fIid\fP gives a 16-bit identifier for the query.
The parameter \fIrd\fP should be nonzero if recursion is desired, zero if not.
The query will be placed in an allocated buffer, a pointer to which will be
stored in the variable pointed to by \fIbuf\fP, and the length of which will
be stored in the variable pointed to by \fIbuflen\fP.
It is the caller's responsibility to free this buffer using
\fIares_free_string(3)\fP when it is no longer needed. The parameter
\fImax_udp_size\fP should be nonzero to activate EDNS. Usage of
\fIares_create_query(3)\fP\ with \fImax_udp_size\fP set to zero is equivalent
to using \fIares_mkquery(3)\fP.
.B ares_create_query
can return any of the following values:
.TP 15
Construction of the DNS query succeeded.
.TP 15
The query name
.I name
could not be encoded as a domain name, either because it contained a
zero-length label or because it contained a label of more than 63
.TP 15
Memory was exhausted.
Added in c-ares 1.10.0
.BR ares_expand_name (3),
.BR ares_free_string (3),
.BR ares_mkquery (3)