    NAME
           gethostbyname, gethostbyaddr, herror, hstrerror - get network host entry

    SYNOPSIS
           #include <network.h>

           struct hostent *gethostbyname(const char *name);

           struct hostent *gethostbyaddr(const char *addr, int len, int type);

           void herror(const char *s);

           const char * hstrerror(int err);

    DESCRIPTION
           The gethostbyname() function returns a structure  of  type
           hostent  for  the  given host name.  Here name is either a
           host name, or an IPv4 address in standard dot notation, or
           an IPv6 address in colon (and possibly dot) notation. (See
           RFC 1884 for the description of IPv6 addresses.)  If  name
           is  an  IPv4  or  IPv6 address, no lookup is performed and
           gethostbyname() simply copies name into the  h_name  field
           and  its struct in_addr equivalent into the h_addr_list[0]
           field of the returned hostent structure.  If name  doesn't
           end  in  a dot and the environment variable HOSTALIASES is
           set, the alias file pointed to by HOSTALIASES  will  first
           be  searched for name.  (See hostname(7) for the file for
           mat.)  The current domain and  its  parents  are  searched
           unless name ends in a dot.

           The  gethostbyaddr()  function returns a structure of type
           hostent for the given host address addr of length len  and
           address  type  type.   The only valid address type is cur
           rently AF_INET.

           The  (obsolete) herror() function prints the error message
           associated with the current value of h_errno on stderr.

           The (obsolete) hstrerror() function takes an error  number
           (typically  h_errno) and returns the corresponding message
           string.

           The domain name queries carried out by gethostbyname() and
           gethostbyaddr()  use  a  combination  of any or all of the
           name server named(8), a broken out line  from  /etc/hosts,
           and the Network Information Service (NIS or YP), depending
           upon the contents of the  order  line  in  /etc/host.conf.
           (See   resolv+(8)).    The  default  action  is  to  query
           named(8), followed by /etc/hosts.

           The hostent structure is defined in <netdb.h> as follows:

                  struct hostent {
                          char    *h_name;        /* official name of host */
                          char    **h_aliases;    /* alias list */
                          int     h_addrtype;     /* host address type */
                          int     h_length;       /* length of address */
                          char    **h_addr_list;  /* list of addresses */
                  }
                  #define h_addr  h_addr_list[0]  /* for backward compatibility */

           The members of the hostent structure are:

           h_name The official name of the host.

           h_aliases
                  A zero-terminated array of  alternative  names  for
                  the host.

           h_addrtype
                  The type of address; always AF_INET at present.

           h_length
                  The length of the address in bytes.

           h_addr_list
                  A  zero-terminated  array  of network addresses for
                  the host in network byte order.

           h_addr The first address in h_addr_list for backward  com
                  patibility.

    RETURN VALUE
           The  gethostbyname()  and gethostbyaddr() functions return
           the hostent structure  or  a  NULL  pointer  if  an  error
           occurs.   On  error,  the  h_errno variable holds an error
           number.

    ERRORS
           The variable h_errno can have the following values:

           HOST_NOT_FOUND
                  The specified host is unknown.

           NO_ADDRESS or NO_DATA
                  The requested name is valid but does not have an IP
                  address.

           NO_RECOVERY
                  A non-recoverable name server error occurred.

           TRY_AGAIN
                  A temporary error occurred on an authoritative name
                  server.  Try again later.