+memcached_return set_prefix(memcached_st *memc)
+{
+ memcached_return rc;
+ const char *key= "mine";
+ char *value;
+
+ /* Make sure be default none exists */
+ value= memcached_callback_get(memc, MEMCACHED_CALLBACK_PREFIX_KEY, &rc);
+ assert(rc == MEMCACHED_FAILURE);
+
+ /* Test a clean set */
+ rc= memcached_callback_set(memc, MEMCACHED_CALLBACK_PREFIX_KEY, (void *)key);
+ assert(rc == MEMCACHED_SUCCESS);
+
+ value= memcached_callback_get(memc, MEMCACHED_CALLBACK_PREFIX_KEY, &rc);
+ assert(memcmp(value, key, 4) == 0);
+ assert(rc == MEMCACHED_SUCCESS);
+
+ /* Test that we can turn it off */
+ rc= memcached_callback_set(memc, MEMCACHED_CALLBACK_PREFIX_KEY, NULL);
+ assert(rc == MEMCACHED_SUCCESS);
+
+ value= memcached_callback_get(memc, MEMCACHED_CALLBACK_PREFIX_KEY, &rc);
+ assert(rc == MEMCACHED_FAILURE);
+
+ /* Now setup for main test */
+ rc= memcached_callback_set(memc, MEMCACHED_CALLBACK_PREFIX_KEY, (void *)key);
+ assert(rc == MEMCACHED_SUCCESS);
+
+ value= memcached_callback_get(memc, MEMCACHED_CALLBACK_PREFIX_KEY, &rc);
+ assert(rc == MEMCACHED_SUCCESS);
+ assert(memcmp(value, key, 4) == 0);
+
+ return MEMCACHED_SUCCESS;
+}
+