+#define HOST_NOT_FOUND 1
+#define TRY_AGAIN 2
+#define NO_RECOVERY 3
+#define NO_DATA 4
+#endif
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+const char *hstrerror(int);
+int gethostbyname_r(const char *, struct hostent *, char *, size_t, struct hostent **, int *);
+int gethostbyname2_r(const char *, int, struct hostent *, char *, size_t, struct hostent **, int *);
+struct hostent *gethostbyname2(const char *, int);
+int gethostbyaddr_r(const void *, socklen_t, int, struct hostent *, char *, size_t, struct hostent **, int *);
+int getservbyport_r(int, const char *, struct servent *, char *, size_t, struct servent **);
+int getservbyname_r(const char *, const char *, struct servent *, char *, size_t, struct servent **);