diff --git a/string/doc/usage.xml b/string/doc/usage.xml
index 142bb2e..56fd3ac 100644
--- a/string/doc/usage.xml
+++ b/string/doc/usage.xml
@@ -130,7 +130,7 @@
     string str1("command.com");
     cout 
         << str1
-        << (is_executable("command.com")? "is": "is not") 
+        << (is_executable(str1)? "is": "is not") 
         << "an executable" 
         << endl; // prints "command.com is an executable"