diff --git a/install/ini.xml b/install/ini.xml
index bf796267df..c7f06cf597 100644
--- a/install/ini.xml
+++ b/install/ini.xml
@@ -134,6 +134,59 @@ include_path = ".;c:\php\lib"
    within .ini files. Example: <literal>open_basedir = ${open_basedir}
    ":/new/dir"</literal>.
   </para>
+  <sect2 xml:id="configuration.file.scan">
+   <title>Scan directories</title>
+
+   <para>
+    It is possible to configure PHP to scan for .ini files in a directory
+    after reading &php.ini;. This can be done at compile time by setting the
+    <option role="configure">--with-config-file-scan-dir</option> option. In
+    PHP 5.2.0 and later, the scan directory can then be overridden at run time
+    by setting the <varname>PHP_INI_SCAN_DIR</varname> environment variable.
+   </para>
+
+   <para>
+    It is possible to scan multiple directories by separating them with the
+    platform-specific path separator (<literal>;</literal> on Windows, NetWare
+    and RISC OS; <literal>:</literal> on all other platforms; the value PHP is
+    using is available as the <constant>PATH_SEPARATOR</constant> constant).
+    If a blank directory is given in <varname>PHP_INI_SCAN_DIR</varname>, PHP
+    will also scan the directory given at compile time via
+    <option role="configure">--with-config-file-scan-dir</option>.
+   </para>
+
+   <para>
+    Within each directory, PHP will scan all files ending in
+    <literal>.ini</literal> in alphabetical order. A list of the files that
+    were loaded, and in what order, is available by calling
+    <function>php_ini_scanned_files</function>, or by running PHP with the
+    <option>--ini</option> option.
+   </para>
+
+   <informalexample>
+    <screen>
+<![CDATA[
+Assuming PHP is configured with --with-config-file-scan-dir=/etc/php.d,
+and that the path separator is :...
+
+$ php
+  PHP will load all files in /etc/php.d/*.ini as configuration files.
+
+$ PHP_INI_SCAN_DIR=/usr/local/etc/php.d php
+  PHP will load all files in /usr/local/etc/php.d/*.ini as
+  configuration files.
+
+$ PHP_INI_SCAN_DIR=:/usr/local/etc/php.d php
+  PHP will load all files in /etc/php.d/*.ini, then
+  /usr/local/etc/php.d/*.ini as configuration files.
+
+$ PHP_INI_SCAN_DIR=/usr/local/etc/php.d: php
+  PHP will load all files in /usr/local/etc/php.d/*.ini, then
+  /etc/php.d/*.ini as configuration files.
+]]>
+    </screen>
+   </informalexample>
+  </sect2>
   <sect2 xml:id="configuration.file.changelog">
    &reftitle.changelog;
 
@@ -160,6 +213,13 @@ include_path = ".;c:\php\lib"
          and will throw a deprecation warning if used.
         </entry>
        </row>
+       <row>
+        <entry>5.2.0</entry>
+        <entry>
+         The <varname>PHP_INI_SCAN_DIR</varname> environment variable can be
+         set to override the scan directory set via the configure script.
+        </entry>
+       </row>
        <row>
         <entry>5.1.0</entry>
         <entry>
diff --git a/reference/info/functions/php-ini-scanned-files.xml b/reference/info/functions/php-ini-scanned-files.xml
index 05e9d82cdd..eb59ef89eb 100644
--- a/reference/info/functions/php-ini-scanned-files.xml
+++ b/reference/info/functions/php-ini-scanned-files.xml
@@ -14,15 +14,13 @@
   </methodsynopsis>
   <para>
    <function>php_ini_scanned_files</function> returns a comma-separated
-   list of configuration files parsed after &php.ini;.  These files are
-   found in a directory defined by the
-   <option role="configure">--with-config-file-scan-dir</option> option
-   which is set during compilation.
+   list of configuration files parsed after &php.ini;. The directories
+   searched are set by a compile time option and, optionally, by an
+   environment variable at run time: more information can be found in the
+   <link linkend="configuration.file.scan">installation guide</link>.
   </para>
   <para>
-   The returned configuration files also include the path as declared in
-   the <option role="configure">--with-config-file-scan-dir</option>
-   option.
+   The returned configuration files include the full path.
   </para>
  </refsect1>
 
@@ -30,12 +28,13 @@
   &reftitle.returnvalues;
   <para>
    Returns a comma-separated string of .ini files on success. Each comma is
-   followed by a newline. If the directive <option
-   role="configure">--with-config-file-scan-dir</option> wasn't set,
-   &false; is returned.  If it was set and the directory was empty, an
-   empty string is returned.  If a file is unrecognizable, the file will
-   still make it into the returned string but a PHP error will also result.
-   This PHP error will be seen both at compile time and while using
+   followed by a newline. If the configure directive <option
+   role="configure">--with-config-file-scan-dir</option> wasn't set and the
+   <varname>PHP_INI_SCAN_DIR</varname> environment variable isn't set, &false;
+   is returned.  If it was set and the directory was empty, an empty string is
+   returned.  If a file is unrecognizable, the file will still make it into
+   the returned string but a PHP error will also result.  This PHP error will
+   be seen both at compile time and while using
    <function>php_ini_scanned_files</function>.
   </para>
  </refsect1>