In brief, here's the error: D:\River Documents\Halloween\2021\src\Lid/setup.ino:19: undefined reference to `_Z8eyes_DIMv' And here is line 19 of setup.ino (I like to use tabs). Serial.println(F("---------- Starting ----------")); I've tried re-typing that line and a few lines before and after …

At the start of compilation, the Arduino IDE makes some small changes to your .ino files to ensure it's valid C++. It will add function prototypes for any function that doesn't already have one. This is intended to make it easier for beginners to write code in the Arduino IDE, and also automates a t…

[image] SteveMann: I like to use tabs Don't. Or at least, glue it all back together while you figure out the issue. I'm not sure what the IDE does precisely, but I recall that it takes all your ino files and combines them (in alphabetical order?) so it may be confused as to where the error i…

_Z8eyes_DIMv is a C++ way to encode symbols in the object file (look up "name mangling"). The name is actually eyes_DIM. Is that symbol referenced anywhere else? Maybe in the definition of something like EYES_PIN in another tab?

[image] wildbill: I'm not sure what the IDE does precisely, but I recall that it takes all your ino files and combines them (in alphabetical order?) so it may be confused as to where the error is. I've never once seen a problem like that. What I have seen is forum regulars spreading FUD about…

I've seen compilation errors in a single ino file caused by the IDE putting prototypes in, so I have little confidence that it is infallible when it comes to munging source files together. YMMV.

Thanks for the tip. I didn't know where to find the cpp file, but that led me tothe solution. There was a protoype for eyes_DIM(), but the function was named eyesDIM. That was a head scratcher. I would have expected a different compile error.

[image] in0: Or maybe consider focusing on finding the problem rather than rearchitecting the sketch just to hide from it? I've seen Gfvalvo comments on tabs before and plan to look at cpp files in a future project. This one is too far along to shift focus now. As I said in another post, the…

I am not disagreeing with you here. I have been using tabs and multiple ino files for a couple of years. This particular sketch has been in development for weeks, so getting this strange compile error was a surprise. Using separate CPP files is likely a better solution than what I have been using,…

[image] wildbill: Maybe consider using cpp files to separate code instead? This is the way to go. Also, while the function prototypes are supposed to be handled automagically, sometimes actually writing them is the cure.

[image] 330R: This is the way to go. I agree, but other than Gvalvo's example, I have never seen anyone use cpp files, so references are not easy to find. But, not in this project. As the comments in the code indicate, this is a Halloween prop and that's only a couple of weeks away.

Help with compile error, please

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gfvalvo October 12, 2021, 6:07pm 5

Then I suggestion doing it the way I describe in Post #5 Here. The "Arduino Way" of multiple .ino files is (IMO) brain-dead.

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Help with compile error, please

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