pollution: gethostbyaddr
struct hostent *gethostbyaddr(const void *, socklen_t, int); 

pollution: gethostbyname
struct hostent *gethostbyname(const char *); 

pollution: HOST_NOT_FOUND
#define HOST_NOT_FOUND 1

pollution: NO_DATA
#define NO_DATA 4

pollution: NO_RECOVERY
#define NO_RECOVERY 3

pollution: TRY_AGAIN
#define TRY_AGAIN 2