以下常量由此扩展定义，只有在将扩展编译到PHP中或在运行时动态加载时才可用。
APC_ITER_ALL (int)APC_ITER_ATIME (int)APC_ITER_CTIME (int)APC_ITER_DEVICE (int)APC_ITER_DTIME (int)APC_ITER_FILENAME (int)APC_ITER_INODE (int)APC_ITER_KEY (int)APC_ITER_MD5 (int)APC_ITER_MEM_SIZE (int)APC_ITER_MTIME (int)APC_ITER_NONE (int)APC_ITER_NUM_HITS (int)APC_ITER_REFCOUNT (int)APC_ITER_TTL (int)APC_ITER_TYPE (int)APC_ITER_VALUE (int)APC_LIST_ACTIVE (int)APC_LIST_DELETED (int)