NAME

dn_expand − Expands a compressed domain name

LIBRARY

Standard C Library (libc.a, libc.so)

SYNOPSIS

#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>

int dn_expand (
    const u_char ∗message_ptr,
    const u_char ∗end_of_message,
    const u_char ∗compressed_name,
    char ∗expanded_name,
    int length );

PARAMETERS

message_ptrSpecifies a pointer to the beginning of a message. 

end_of_message
Points to the end of the original message that contains the compressed domain name.

compressed_name
Specifies a pointer to a compressed domain name.

expanded_name
Specifies a pointer to a buffer that holds the resulting expanded domain name.

lengthSpecifies the size of the buffer pointed to by the expanded_name parameter. 

DESCRIPTION

The dn_expand() function expands a compressed domain name to a full domain name, converting the expanded names to uppercase. 

The dn_expand() function is one of a set of subroutines that form the resolver, a set of functions that resolves domain names.  Global information that is used by the resolver functions is kept in the _res data structure.  The  /include/resolv.h file contains the _res structure definition. 

RETURN VALUES

Upon successful completion, the dn_expand() function returns the size of the compressed domain name.  Otherwise, a value of -1 is returned. 

ERRORS

If an error occurs during a resolver operation, the h_errno external variable is set.  Error code values and reasons are defined in <netdb.h>. 

FILES

/etc/resolv.conf
Defines name server and domain name constants, structures, and values.

RELATED INFORMATION

Functions: dn_comp(3), dn_find(3), dn_skipname(3), putshort(3), putlong(3), res_init(3), res_mkquery(3), res_query(3), res_search(3), res_send(3), _getshort(3), _getlong(3).