Use this macro to start an extension module interface function. The macro argument X is the name of the function as it is used in the BASIC statement
declare sub ::Function alias "X" lib "module"
This macro handles all system dependant function decoration declarations and declares the argument variables. Altough it is possible to name the argument variables in a different way it is strongly recommended that the programmer writing external module uses this macro and thus uses the argument names, because the besXXX macros rely on these variable names.