GLOBAL var1, var2$...,varN

This statement specifies that the variables listed are global in scope.  They are visible inside functions and subroutines as well as in the main program code.  Global variables can be modified inside functions and subroutines as well, so care must be taken not to alter them accidentally, because this can easily cause errors in the program that are difficult to isolate. Use global variables for things like values for true and false, file paths, user preferences etc.

Special Globals

The special capitalized globals (like WindowWidth, DefaultDir$, the color setting variables, etc.) are global variables. 