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Mornin' Greg:

Yes, Al and I found a lot of "dead" variables when we started out. We could tell by their names that some of them were clearly used as temporary debug variables that just didn't get cleared out. We also found a bunch of "dead" functions that were never called anywhere. We tried to remove all of those, but I know some were not removed. At one time, I thought some of these might be resued later on, but ended up not being used. I just never when back to clean them out.

"De-globalizing" the code is a little harder when the variable is used in multiple unrelated functions. In those cases, the variable could be defined in the ino file, but passed to the other functions (as a pointer?) as needed. That does de-clutter things, but is a pain to do. However, if you can isolate the variable to only the file that uses it, the problem is more manageable. Example: If a variable is only used in the display.cpp source file, it can be localized to that file. It sounds like that's what you've done: create a header file for each "functional" cpp file. The reason I didn't do this is because, as you pointed out, it means each cpp file has its own header file, which has the effect of doubling the number of file which is its own form of clutter, albeit it is organized clutter.?

For such global variables that are only used in one cpp file, instead of placing them their own header file (e.g., display.h which ties to display.cpp), you could place those "local globals" in the cpp file, but use the static storage specifier for them. This keyword is more of an attention-gettter to the programmer than a difference in the variable's placement in memory. I say that because, if you define the variable in the display.cpp file outside of a function without the static specifier, it has global scope, but only for the file in which it is defined. If that variable is not called in any other cpp file, you won't get the "undefined" error message. The only thing the static keyword does is allow you to use that same variable name in multiple cpp files and still not generate a "multiply defined" error message. (I don't know why you'd want to do that, but you could!) The only reason I would add the static keyword in this case is to serve as a sentinel to tell other programmers that this is a "local global".

Jack, W8TEE