ares_gethostbyname.txt

RTL-lwIP is the porting of the lwIP TCP/IP stack to RTLinux-GPL.The focus of the RTL-lwIP stack is

ARES_GETHOSTBYNAME(3)                                    ARES_GETHOSTBYNAME(3)



NAME
       ares_gethostbyname - Initiate a host query by name

SYNOPSIS
       #include <ares.h>

       typedef void (*ares_host_callback)(void *arg, int status,
       struct hostent *hostent)

       void ares_gethostbyname(ares_channel channel, const char *name,
            int family, ares_host_callback callback, void *arg)

DESCRIPTION
       The  ares_gethostbyname  function initiates a host query by name on the
       name service channel identified by channel.  The parameter  name  gives
       the hostname as a NUL-terminated C string, and family gives the desired
       type of address for the resulting host entry.  When the query  is  com-
       plete or has failed, the ares library will invoke callback.  Completion
       or failure of the query may happen immediately, or may happen during  a
       later call to ares_process(3) or ares_destroy(3).

       The  callback  argument arg is copied from the ares_gethostbyname argu-
       ment arg.  The callback argument status  indicates  whether  the  query
       succeeded and, if not, how it failed.  It may have any of the following
       values:

       ARES_SUCCESS       The host lookup completed successfully.

       ARES_ENOTIMP       The ares library does not know how to find addresses
                          of type family.

       ARES_EBADNAME      The  hostname  name  is composed entirely of numbers
                          and periods, but is not a valid representation of an
                          Internet address.

       ARES_ENOTFOUND     The address addr was not found.

       ARES_ENOMEM        Memory was exhausted.

       ARES_EDESTRUCTION  The name service channel channel is being destroyed;
                          the query will not be completed.

       On successful completion of the query, the  callback  argument  hostent
       points  to a struct hostent containing the name of the host returned by
       the query.  The callback need not and should not attempt  to  free  the
       memory  pointed  to  by hostent; the ares library will free it when the
       callback returns.  If the query did not complete successfully,  hostent
       will be NULL.

SEE ALSO
       ares_process(3)

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



                                 25 July 1998            ARES_GETHOSTBYNAME(3)