Where can I find the code for Arduino's attachInterrupt function?

A search on the Arduino's Github repo yielded nothing.

I suspect it might be a wrapper for some avr-libc function but nothing in the avr-libc docs stands out to me...

  • download a text editor like Notepad++ ..... you can then use it to search for text in folders (directories) ..... search for the text "attachInterrupt" in the arduino install directory .... it will find all files that contain that word ..... get it here notepad-plus-plus.org
    – jsotola
    Jun 9, 2018 at 6:20

1 Answer 1


It's in the core in WInterrupts.c

On my install it's at:



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