APC Object Cache provides a persistent memory-based backend for the WordPress object cache. APC must be available on your PHP install.
die()when people mistakenly try to activate this as a plugin, and provide a helpful message for where they should move the file
md5( ABSPATH )calculation once per load (props jdub)
wp-config.phpsetups to define
WP_APC_KEY_SALTto guarantee key uniqueness (props jdub)
incr2and then conditionally add
incrvia class extension (so that Batcache can properly detect incrementor support)