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[Reply #15 on:]

so a single cpp file can only have one class in it? all functions are considered part of the class?

Perhaps I am misunderstanding... I want to split my midi related stuff out of my main sketch into a midi.cpp file... part of this midi related stuff is the class, but not all of it.  Am I to understand that I cannot have a global function and a class in a single cpp file?

[Reply #16 on:]

so a single cpp file can only have one class in it? all functions are considered part of the class?

No and no. If the function is declared inside a class, it must be implemented as a class method, using the
ReturnType ClassName::MethodName(ArgType arg)
format.

If the function is declared outside the class, it is a global method, but it does not have access to variables defined in other files, unless the extern keyword is used to import the variable into the file scope.

Perhaps I am misunderstanding... I want to split my midi related stuff out of my main sketch into a midi.cpp file... part of this midi related stuff is the class, but not all of it.  Am I to understand that I cannot have a global function and a class in a single cpp file?

You can have non-class members in the file. But, those non-class members can not call methods in a class without an instance of that class. If the instance is declared in another file, that instance must be imported using the extern keyword.

[Reply #17 on:]

ok... the light bulb is getting brighter...

Code:

extern MyMidi midi(Serial);

in midi.cpp would take care of things then right?

[Reply #18 on:]

Code:

extern MyMidi midi(Serial);

in midi.cpp would take care of things then right?

Close. The variable midi is declared and initialized in one file using

Code:

MyMidi midi(Serial);

To reference that already initialized variable in another file:

Code:

extern MyMidi midi;