# APC User Cache

- Introduction
- Installing/Configuring
  - Requirements
  - Installation
  - Runtime Configuration
  - Resource Types
- Predefined Constants
- APCu Functions
  - apcu_add — Cache a new variable in the data store
  - apcu_cache_info — Retrieves cached information from APCu's data store
  - apcu_cas — Updates an old value with a new value
  - apcu_clear_cache — Clears the APCu cache
  - apcu_dec — Decrease a stored number
  - apcu_delete — Removes a stored variable from the cache
  - apcu_enabled — Whether APCu is usable in the current environment
  - apcu_entry — Atomically fetch or generate a cache entry
  - apcu_exists — Checks if entry exists
  - apcu_fetch — Fetch a stored variable from the cache
  - apcu_inc — Increase a stored number
  - apcu_sma_info — Retrieves APCu Shared Memory Allocation information
  - apcu_store — Cache a variable in the data store
- APCUIterator — The APCUIterator class
  - APCUIterator::__construct — Constructs an APCUIterator iterator object
  - APCUIterator::current — Get current item
  - APCUIterator::getTotalCount — Get total count
  - APCUIterator::getTotalHits — Get total cache hits
  - APCUIterator::getTotalSize — Get total cache size
  - APCUIterator::key — Get iterator key
  - APCUIterator::next — Move pointer to next item
  - APCUIterator::rewind — Rewinds iterator
  - APCUIterator::valid — Checks if current position is valid