php man page for touch

TOUCH(3)								 1								  TOUCH(3)

touch - Sets access and modification time of file

SYNOPSIS
       bool touch (string  $filename, [int  $time = time()], [int  $atime])

DESCRIPTION
	Attempts  to set the access and modification times of the file named in the $filename parameter to the value given in $time. Note that the
       access time is always modified, regardless of the number of parameters.

	If the file does not exist, it will be created.

PARAMETERS
	      o $filename
		- The name of the file being touched.

	      o $time
		- The touch time. If $time is not supplied, the current system time is used.

	      o $atime
		- If present, the access time of the given filename is set to the value of $atime. Otherwise, it is set to the value passed to the
		$time parameter. If neither are present, the current system time is used.

RETURN VALUES
	Returns TRUE on success or FALSE on failure.

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.3.0	|						    |
       |	|						    |
       |	|  It  became  possible  to change the modification |
       |	| time of a directory under Windows.		    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      touch(3) example

	      <?php
	      if (touch($filename)) {
		  echo $filename . ' modification time has been changed to present time';
	      } else {
		  echo 'Sorry, could not change modification time of ' . $filename;
	      }
	      ?>

       Example #2

	      touch(3) using the $time parameter

	      <?php
	      // This is the touch time, we'll set it to one hour in the past.
	      $time = time() - 3600;

	      // Touch the file
	      if (!touch('some_file.txt', $time)) {
		  echo 'Whoops, something went wrong...';
	      } else {
		  echo 'Touched file with success';
	      }
	      ?>

NOTES
       Note

	      Note that time resolution may differ from one file system to another.

       Warning

	       Prior to PHP 5.3.0 it was not possible to change the modification time of a directory with this function under Windows.

PHP Documentation Group 														  TOUCH(3)