ares_mkquery.3

这是国外的resip协议栈

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.TH ARES_MKQUERY 3 "4 January 2000"
.SH NAME
ares_mkquery \- Compose a single-question DNS query buffer
.SH SYNOPSIS
.nf
.B #include <ares.h>
.PP
.B
int ares_mkquery(const char *\fIname\fP, int \fIdnsclass\fP, int \fItype\fP,
.B
	unsigned short \fIid\fP, int \fIrd\fP, char **\fIbuf\fP,
	int *\fIbuflen\fP)
.fi
.SH DESCRIPTION
The
.B ares_mkquery
function composes a DNS query with a single question.
The parameter
.I name
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
.I dnsclass
and
.I type
give the class and type of the query using the values defined in
.BR <arpa/nameser.h> .
The parameter
.I id
gives a 16-bit identifier for the query.  The parameter
.I rd
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
.IR buf ,
and the length of which will be stored in the variable pointed to by
.IR buflen .
It is the caller's responsibility to free this buffer using
.B ares_free_string
when it is no longer needed.
.SH RETURN VALUES
.B ares_mkquery
can return any of the following values:
.TP 15
.B ARES_SUCCESS
Construction of the DNS query succeeded.
.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 SEE ALSO
.BR ares_expand_name (3),
.BR ares_free_string (3)
.SH AUTHOR
Greg Hudson, MIT Information Systems
.br
Copyright 1998, 2000 by the Massachusetts Institute of Technology.