Lock Fn keys on K400+ (for windows)

This program locks the fn key for the Logitech K400+ bluetooth keyboard on Windows. Having the F1-F12 without pressing the Fn key is nice for developers.

I wanted a simple way to do the same as the Logitech Options/Options+ softwares WITHOUT their continuously running processes.

Precompiled binaries available here : https://github.com/h8man/k400p-fn-lock-win/releases

Running k400p-fn-lock.exe will lock Fn key till next reboot. You may want to add into Task Scheduler or pin to taskbar. Revert with k400p-fn-unlocklock.exe to unlock and restore media keys.

Running tray.exe will lunch tray app where you'll have options to Fn (Un)Lock your keyboard

Running add_startup_tray.bat will put tray app on startup.

• build with gcc:
  gcc main.c -o dist/k400p-fn-lock.exe -I hidapi/include -L hidapi/x86 -lhidapi
gcc main.c -D setMediaKeys -o dist/k400p-fn-unlock.exe -I hidapi/include -L hidapi/x86 -lhidapi
• build with msvc: build.bat build_tray.bat

• code from : https://github.com/dheygere/k380-fn-lock-for-windows
• values from : https://github.com/sginne/fn_key_k400_for_logitech