usr/src/include/netdb.h

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *      @(#)netdb.h     5.6 (Berkeley) %G%
 */

/*
 * Structures returned by network
 * data base library.  All addresses
 * are supplied in host order, and
 * returned in network order (suitable
 * for use in system calls).
 */
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 from name server */
#define h_addr  h_addr_list[0]  /* address, for backward compatiblity */
};

/*
 * Assumption here is that a network number
 * fits in 32 bits -- probably a poor one.
 */
struct  netent {
        char            *n_name;        /* official name of net */
        char            **n_aliases;    /* alias list */
        int             n_addrtype;     /* net address type */
        unsigned long   n_net;          /* network # */
};

struct  servent {
        char    *s_name;        /* official service name */
        char    **s_aliases;    /* alias list */
        int     s_port;         /* port # */
        char    *s_proto;       /* protocol to use */
};

struct  protoent {
        char    *p_name;        /* official protocol name */
        char    **p_aliases;    /* alias list */
        int     p_proto;        /* protocol # */
};

struct hostent  *gethostbyname(), *gethostbyaddr(), *gethostent();
struct netent   *getnetbyname(), *getnetbyaddr(), *getnetent();
struct servent  *getservbyname(), *getservbyport(), *getservent();
struct protoent *getprotobyname(), *getprotobynumber(), *getprotoent();

/*
 * Error return codes from gethostbyname() and gethostbyaddr()
 */

extern  int h_errno;

#define HOST_NOT_FOUND  1 /* Authoritive Answer Host not found */
#define TRY_AGAIN       2 /* Non-Authoritive Host not found, or SERVERFAIL */
#define NO_RECOVERY     3 /* Non recoverable errors, FORMERR, REFUSED, NOTIMP */
#define NO_ADDRESS      4 /* Valid host name, no address, look for MF record */