ares_expand_name man page

ares_expand_name — Expand a DNS-encoded domain name


#include <ares.h>

int ares_expand_name(const unsigned char *encoded,
const unsigned char *abuf, int alen, char **s,
long *enclen)


The ares_expand_name function converts a DNS-encoded domain name to a dot-separated C string.  The argument encoded gives the beginning of the encoded domain name, and the arguments abuf and alen give the containing message buffer (necessary for the processing of indirection pointers within the encoded domain name).  The result is placed in a NUL-terminated allocated buffer, a pointer to which is stored in the variable pointed to by s. The length of the encoded name is stored in the variable pointed to by enclen so that the caller can advance past the encoded domain name to read further data in the message.

Use ares_free_string(3) to free the allocated hostname.

Return Values

ares_expand_name can return any of the following values:


Expansion of the encoded name succeeded.


The encoded domain name was malformed and could not be expanded.


Memory was exhausted.

See Also



Greg Hudson, MIT Information Systems
Copyright 1998 by the Massachusetts Institute of Technology.

Referenced By

ares_create_query(3), ares_mkquery(3).

20 Nov 2009