 During software development, null functions with the same names and type signatures as a planned functions are often used as stubs—that is, as non-functional placeholders that allow the incomplete body of code to be compiled and tested prior to completion of all planned features.Null functions, particularly the NOP variety, are also used to provide delays of indeterminate length within wait loops.This is a common strategy in dedicated device controllers that must wait for an external input and have no other tasks to perform while they are waiting.