asmc is a library of low-level interface that allow you to read / write values to the SMC using the AppleSMC kernel extension with C. You can read the temperature of the sensors, get the fan speeds etc. The source code does not belong to me. I only edited, added, modified, enchanged the codes in a way that I need.

This tool will allow you to read / write values to the SMC which could or could not irreversably damage your computer. Especially manipulating the fans could cause overheating and permanent damange. USE THIS PROGRAM AT YOUR OWN RISK!

make

./asmc

or

sudo make install # installs to /usr/local/bin
asmc

func callCFunction() {
  SMCOpen()
  readAndPrintFanRPMs()
  ...
  SMCClose()
}

Works both on Intel and Apple Silicon based Macbooks.

Tested on 2018 15″ Intel Macbook Pro & 2021 14″ M1 Max Macbook Pro

I might have looked up and took inspiration from other places as well. These are the ones that I can remember.

• https://developer.apple.com/documentation/kernel/iokit_fundamentals
• https://github.com/lavoiesl/osx-cpu-temp
• https://github.com/spotify/linux/blob/master/drivers/hwmon/applesmc.c
• https://stackoverflow.com/a/31033665/8937209
• https://github.com/acidanthera/VirtualSMC/blob/master/Docs/SMCSensorKeys.txt
• https://github.com/exelban/stats
• https://github.com/dkorunic/iSMC

Apple System Management Control (SMC) Tool Copyright (C) 2006

This project is under GPL-3.0 License