php man page for is_uploaded_file

IS_UPLOADED_FILE(3)							 1						       IS_UPLOADED_FILE(3)

is_uploaded_file - Tells whether the file was uploaded via HTTP POST

SYNOPSIS
       bool is_uploaded_file (string  $filename)

DESCRIPTION
	Returns  TRUE  if the file named by $filename was uploaded via HTTP POST. This is useful to help ensure that a malicious user hasn't tried
       to trick the script into working on files upon which it should not be working--for instance, /etc/passwd.

	This sort of check is especially important if there is any chance that anything done with uploaded files could reveal  their  contents	to
       the user, or even to other users on the same system.

	For  proper  working,  the function is_uploaded_file(3) needs an argument like $_FILES['userfile']['tmp_name'], - the name of the uploaded
       file on the client's machine $_FILES['userfile']['name'] does not work.

PARAMETERS
	      o $filename
		- The filename being checked.

RETURN VALUES
	Returns TRUE on success or FALSE on failure.

EXAMPLES
       Example #1

	      is_uploaded_file(3) example

	      <?php

	      if (is_uploaded_file($_FILES['userfile']['tmp_name'])) {
		 echo "File ". $_FILES['userfile']['name'] ." uploaded successfully.
";
		 echo "Displaying contents
";
		 readfile($_FILES['userfile']['tmp_name']);
	      } else {
		 echo "Possible file upload attack: ";
		 echo "filename '". $_FILES['userfile']['tmp_name'] . "'.";
	      }

	      ?>

SEE ALSO
       move_uploaded_file(3), $_FILES, See Handling file uploads for a simple usage example..

PHP Documentation Group 												       IS_UPLOADED_FILE(3)