Merge fix for bug 14521 from 1.5 branch

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@274284 13f79535-47bb-0310-9956-ffa450edef68

docs/manual/using.html

@@ -85,7 +85,9 @@ control on the building process depending on the state of the system
 (java version, OS, command-line property defines, etc.).  To make a target
 <i>sense</i> this property, you should add the <code>if</code> (or
 <code>unless</code>) attribute with the name of the property that the target
-should react to. For example:</p>
+should react to. <strong>Note:</strong> Ant will only check whether
+the property has been set, the value doesn't matter.  A property set
+to the empty string is still an existing property.  For example:</p>
 <blockquote>
   <pre>&lt;target name=&quot;build-module-A&quot; if=&quot;module-A-present&quot;/&gt;</pre>
   <pre>&lt;target name=&quot;build-own-fake-module-A&quot; unless=&quot;module-A-present&quot;/&gt;</pre>
@@ -147,18 +149,16 @@ have the name <code>&quot;init&quot;</code>.</p>
 </table>
 </p>
 
-A target name can be any alphanumeric string valid in the encoding of the XML
+<p>A target name can be any alphanumeric string valid in the encoding of the XML
 file. The empty string &quot;&quot; is in this set, as is
 comma &quot;,&quot; and space &quot; &quot;.
 Please avoid using these, as they will not be supported in future Ant versions
 because of all the confusion they cause. IDE support of unusual target names,
-or any target name containing spaces, varies with the IDE.
+or any target name containing spaces, varies with the IDE.</p>
 
-<p>
-
-Targets beginning with a hyphen such as <code>&quot;-restart&quot;</code>
+<p>Targets beginning with a hyphen such as <code>&quot;-restart&quot;</code>
 are valid, and can be used
-to name targets that should not be called directly from the command line.
+to name targets that should not be called directly from the command line.</p>
 
 <h3><a name="tasks">Tasks</a></h3>
 <p>A task is a piece of code that can be executed.</p>
@@ -535,7 +535,7 @@ href="CoreTypes/patternset.html">PatternSet</a>s, <a href="CoreTypes/fileset.htm
 structures as well.</p>
 
 <hr>
-<p align="center">Copyright &copy; 2000-2002 Apache Software Foundation. All rights
+<p align="center">Copyright &copy; 2000-2003 Apache Software Foundation. All rights
 Reserved.</p>
 
 </body>