Adds filtername to the
list of filters attached to
stream. This filter will be added with the specified
params to the end of the list and
will therefore be called last during stream opperations. To
add a filter to the beginning of the list, use
stream_filter_prepend().
注: stream_register_filter() must be called first in order to register the desired user filter to filtername.
See Also:
stream_register_filter(), and
stream_filter_prepend()