What is realpath_cache in PHP?

Question

Can anyone tell me what exactly is meant by realpath_cache in PHP? Lots of references have been made to it in the PHP manual, but nothing explains it adequately

Answer 1

realpath_cache is the system that allows php to cache paths to locations of files/directories you are using to minimize expensive disk lookups. It could possibly greatly improve performance of you PHP application/site if you use alot of relative file paths PHP has to parse/lookup each time you reference them.