char **keys, size_t *key_length,
unsigned int number_of_keys);
char *memcached_fetch (memcached_st *ptr,
char *key, size_t *key_length,
size_t *value_length,
char **keys, size_t *key_length,
unsigned int number_of_keys);
char *memcached_fetch (memcached_st *ptr,
char *key, size_t *key_length,
size_t *value_length,