A collection of 19 tips on creating your own PHP functions. Clear answers are provided with tutorial exercises on defining functions, defining arguments, passing references, returning references, argument default values, etc. Special topics are: How To Pass Variables By References? How Arrays Are Passed Through Arguments? How To Pass Arrays By References? How To Return an Array from a Function? What Is the Scope of a Variable Defined in a Function? How To Access a Global Variable inside a Function? How To Return a Reference from a Function? How To Specify Argument Default Values? How To Define a Function with Any Number of Arguments?