Adding RadioHead library to Arduino sketch

Question

I am working on a project to use Arduino heart rate pulse wirelessly. My issue is when I add the RadioHead library to the existing generic heart pulse code; it is conflicting.

To be precise, it is conflicting with the interrupt section only. I read a bit on the Internet, and I guess I have a library conflict... But there aren't any other libraries in use.

When I try upload the sketch only after adding RadioHead:

#include <RH_ASK.h>

I get the following message:

C:\Users\namee\AppData\Local\Temp\cc9lzNai.ltrans2.ltrans.o: In function `main':

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/main.cpp:43: undefined reference to `setup'

collect2.exe: error: ld returned 1 exit status

exit status 1
Error compiling for board Arduino Leonardo.

Answer 1

The cause of the error, as was already explained to you by sterretje in your cross post of this question to the Arduino Forum:

You simply did not write a setup() function in your sketch; nothing to do with a library conflict.

The Arduino convention is that every sketch should have a setup() and loop() function, even if they are left empty. In the Arduino core library there is a main() definition that calls these functions, thus the error you encountered when you didn't define setup() in your sketch. I find this to be a reasonable approach to making programming as beginner friendly as possible and it's useful for just about every project I've done. If for some reason you miss the standard main() of C++ then you can define your own main() in the sketch, where it will override the definition in main.cpp. However, I would recommend against doing that unless you have good reason.