made the specs more clear

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402657

dlib/misc_api/misc_api_kernel_abstract.h

@@ -61,8 +61,8 @@ namespace dlib
         throws
             - dir_create_error
                 This exception is thrown if we were unable to create the requested
-                directory.  The type member of the exception will bet set to
-                EDIR_CREATE and the name member will be set to dir.
+                directory and it didn't already exist.  The type member of the exception 
+                will bet set to EDIR_CREATE and the name member will be set to dir.
     !*/
 
 // ----------------------------------------------------------------------------------------