+ document feof() pitfall if invalid handle passed

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@196438 c90b9560-bf6c-de11-be94-00142212c4b1

reference/filesystem/functions/feof.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.9 $ -->
+<!-- $Revision: 1.10 $ -->
 <!-- splitted from ./en/functions/filesystem.xml, last change in rev 1.2 -->
   <refentry id="function.feof">
    <refnamediv>
@@ -26,6 +26,26 @@
       </simpara>
      </warning>
      &fs.validfp.all;
+     <warning>
+       If passed file pointer is not valid you may get an infinite loop, because
+       EOF fails to return TRUE.
+       <example>
+        <programlisting role="php">
+ <![CDATA[
+<?php
+// if file can not be read or doesn't exist fopen function returns FALSE
+$file = @fopen("no_such_file", "r");
+
+// FALSE from fopen will issue warning and result in infinite loop here
+while (!feof($file)) {
+}
+
+fclose($file);
+?>
+?]]>
+        </programlisting>
+       </example>
+     </warning>
    </refsect1>
   </refentry>