[ci skip] Update info on function_usable
diff --git a/system/core/Common.php b/system/core/Common.php
index e5dd843..07f0c6d 100644
--- a/system/core/Common.php
+++ b/system/core/Common.php
@@ -756,6 +756,11 @@
 	 * *suhosin.executor.disable_eval*. These settings will just
 	 * terminate script execution if a disabled function is executed.
 	 *
+	 * The above described behavior turned out to be a bug in Suhosin,
+	 * but even though a fix was commited for 0.9.34 on 2012-02-12,
+	 * that version is yet to be released. This function will therefore
+	 * be just temporary, but would probably be kept for a few years.
+	 *
 	 * @link	http://www.hardened-php.net/suhosin/
 	 * @param	string	$function_name	Function to check for
 	 * @return	bool	TRUE if the function exists and is safe to call,
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 3124dea..c6d42d9 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -449,7 +449,7 @@
       -  Changed ``_exception_handler()`` to respect php.ini *display_errors* setting.
       -  Added function :php:func:`is_https()` to check if a secure connection is used.
       -  Added function :php:func:`is_cli()` to replace the ``CI_Input::is_cli_request()`` method.
-      -  Added function :php:func:`function_usable()` to check if a function exists and is not disabled by `Suhosin <http://www.hardened-php.net/suhosin/>`.
+      -  Added function :php:func:`function_usable()` to work around a bug in `Suhosin <http://www.hardened-php.net/suhosin/>`.
       -  Removed the third (`$php_error`) from function :php:func:`log_message()`.
 
    -  :doc:`Output Library <libraries/output>` changes include:
diff --git a/user_guide_src/source/general/common_functions.rst b/user_guide_src/source/general/common_functions.rst
index a1007cb..1babe5a 100644
--- a/user_guide_src/source/general/common_functions.rst
+++ b/user_guide_src/source/general/common_functions.rst
@@ -202,4 +202,9 @@
 
 It is useful if you want to check for the availability of functions
 such as ``eval()`` and ``exec()``, which are dangerous and might be
-disabled on servers with highly restrictive security policies.
\ No newline at end of file
+disabled on servers with highly restrictive security policies.
+
+.. note:: This function was introduced because Suhosin terminated
+	script execution, but this turned out to be a bug. A fix
+	has been available for some time (version 0.9.34), but is
+	unfortunately not released yet.
\ No newline at end of file