Stream Errors
As with any file or socket related function, an operation on a stream
may fail for a variety of normal reasons (i.e.: Unable to connect to remote
host, file not found, etc...). A stream related call may also fail because
the desired stream is not registered on the running system. See the array returned
by stream_get_wrappers() for a list of streams supported by your
installation of PHP. As with most PHP internal functions
if a failure occurs an E_WARNING message will be generated
describing the nature of the error.
Stream Contexts
