.\" .\" 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. .\" .\" SPDX-License-Identifier: MIT .\" .TH ARES_CREATE_QUERY 3 "17 Aug 2012" .SH NAME ares_create_query \- Compose a single-question DNS query buffer .SH SYNOPSIS .nf #include 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) .fi .SH DESCRIPTION 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\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. .SH RETURN VALUES .B ares_create_query can return any of the following values: .TP 15 .B ARES_SUCCESS Construction of the DNS query succeeded. .TP 15 .B ARES_ENOTFOUND The query name .I name refers to a .I .onion domain name. See RFC 7686. .TP 15 .B ARES_EBADNAME 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 characters. .TP 15 .B ARES_ENOMEM Memory was exhausted. .SH AVAILABILITY Added in c-ares 1.10.0 .SH SEE ALSO .BR ares_dns_record (3), .BR ares_expand_name (3), .BR ares_free_string (3), .BR ares_mkquery (3) .SH AUTHOR