Removes a stream filter previously added to a stream with stream_filter_prepend() or stream_filter_append(). Any data remaining in the filter's internal buffer will be flushed through to the next filter before removing it.
/* Open a test file for reading and writing */
$fp = fopen("test.txt", "rw");
$rot13_filter = stream_filter_append($fp, "string.rot13", STREAM_FILTER_WRITE);
fwrite($fp, "This is ");
fwrite($fp, "a test\n");
/* Expected Output
Guvf vf a test