a wrapper is additional code which tells the stream how to handle specific protocolsencodings for example the http wrapper knows how to translate a url into an http 10 request for a file on a remote server there are many wrappers built into php by default see ふろく i and additional custom wrappers may be added either within a php script using stream _ register _ wrapper or directly from an extension using the api reference in だい 43 しょう because any variety of wrapper may be added to php there is no set limit on what can be done with them to access the list of currently registered wrappers use stream _ get _ wrappers 