Hello I do not know if the help file is well explained, because of my translation from Portuguese to English, but I hope you enjoy. This dependence of the UDF has Runex, but if you do not want to use, then do not use the optional parameter. If you have any questions you can ask, I made a video as well, why think it's better than all this explanation.

Source:
http://phpaste.sourceforge.net/demo/?paste=35#
http://1drv.ms/1Myd6Op