Does PHP close the file after the file handler is garbage collected?

Question

If I have a short function that opens a file and reads a line, do I need to close the file? Or will PHP do this automatically when execution exits the function and $fh is garbage collected?

function first_line($file) {     $fh = fopen($file);     $first_line = fgets($fh);     fclose($fh);     return $first_line; } 

could then be simplified to

function first_line($file) {     return fgets(fopen($file)); } 

This is of course theoretical right now, as this code doesn't have any error handling.

Answer 1

PHP automatically runs the resource destructor as soon as all references to that resource are dropped.

As PHP has a reference-counting based garbage collection you can be fairly sure that this happens as early as possible, in your case as soon as $fh goes out of scope.

Before PHP 5.4 fclose didn't actually do anything if you tried to close a resource that had more than two references assigned to it.

Answer 2

Yes. Resources are released automatically when they go out of scope. To wit:

<?php  class DummyStream {      function stream_open($path, $mode, $options, &$opened_path) {     echo "open $path<br>";         return true;     }      function stream_close() {         echo "close<br>";         return true;     } }  stream_wrapper_register("dummy", "DummyStream");  function test() {     echo "before open<br>";     fopen("dummy://hello", "rb");     echo "after open<br>"; }  test();  ?> 

Output:

before open open dummy://hello close after open 

The file handle is released as soon as fopen() returns, as there's nothing here capturing the handle.