Why do we need to export GPIOs? Why isn't this done in the code?

[8483]

Why is this step needed? I don't understand it, can you please help me out?
Why isn't this done in the code?

#!/bin/sh
echo 17 > /sys/class/gpio/export
echo in > /sys/class/gpio/gpio17/direction
echo both > /sys/class/gpio/gpio17/edge

[bestpika]

@8483 You can see this, or you can change epoll to onoff.

[8483]

@bestpika Still doesn't answer the question why this is not a part of the code?

Why does it have to be done via the terminal, when the GPIOs can be initialized via code, like you said in onoff?

[bestpika]

Because the library (epoll) didn't write it.
Another library (onoff, same author) write it.
Or you can use my modified version.
It changes the library from epoll to onoff.

[samt]

Sorry for the late reply (> 1yr). So this was written with a custom pi HAT in mind, which had an EEPROM that did this stuff for you. There are other situations where you may already be doing this in a startup script because your node app is decoupled from the hardware setup.