(PHP 5, PHP 7, PHP 8)
stream_copy_to_stream — Copies data from one stream to another
$from,$to,$length = null,$offset = 0
   Makes a copy of up to length bytes
   of data from the current position (or from the
   offset position, if specified) in
   from to to. If
   length is null, all remaining content in
   from will be copied.
  
fromThe source stream
toThe destination stream
lengthMaximum bytes to copy. By default all bytes left are copied.
offsetThe offset where to start to copy data
   Returns the total count of bytes copied, or false on failure.
  
| Version | Description | 
|---|---|
| 8.0.0 | lengthis now nullable. | 
Example #1 A stream_copy_to_stream() example
<?php
$src = fopen('http://www.example.com', 'r');
$dest1 = fopen('first1k.txt', 'w');
$dest2 = fopen('remainder.txt', 'w');
echo stream_copy_to_stream($src, $dest1, 1024) . " bytes copied to first1k.txt\n";
echo stream_copy_to_stream($src, $dest2) . " bytes copied to remainder.txt\n";
?>