glibc/include/resolv.h

#ifndef _RESOLV_H_

#define RES_SET_H_ERRNO(r,x)			\
  do						\
    {						\
      (r)->res_h_errno = x;			\
      __set_h_errno(x);				\
    }						\
  while (0)

#include <resolv/resolv.h>

/* Now define the internal interfaces.  */
extern int __res_vinit (res_state, int);
extern void _sethtent (int);
extern void _endhtent (void);
extern struct hostent *_gethtent (void);
extern struct hostent *_gethtbyname (const char *__name);
extern struct hostent *_gethtbyname2 (const char *__name, int __af);
struct hostent *_gethtbyaddr (const char *addr, size_t __len, int __af);
extern u_int32_t _getlong (const u_char *__src);
extern u_int16_t _getshort (const u_char *__src);
extern void res_pquery (const res_state __statp, const u_char *__msg,
			int __len, FILE *__file);
extern void res_send_setqhook (res_send_qhook __hook);
extern void res_send_setrhook (res_send_rhook __hook);
extern int res_ourserver_p (const res_state __statp,
			    const struct sockaddr_in6 *__inp);

#endif