another question: why is this a ".h" file anyway? I thought header files are meant to be for pre-declarations, whereas this file is just code ?
The preprocessor doesn't care what type of file you try to include. You could include a .cpp file or a .jpeg file if you wanted to. By convention, though, only .h files are #included.
Typically, a header file contains declarations only, but there isn't anything to preclude having executable code in the header file.
Partly for my education, partly because it stands out as an annoying exception - none of my other function calls require me to include anything.
What other function calls are you referring to? You should see some of the files I create for work. Some of them have 40 or 50 other header files included. Don't complain about having to include one lousy file...
I did try cut and paste recently but I get this error: 'FloatToString' was not declared in this scope??
So, we'd need to see how you did it. Generally, all ino files are merged for compilation as a single file. so the function should be in scope.
could you provide a pointer to info about that call please?
Sure, but so can google, so, I'll defer.