下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
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)