onChange Event to be triggered if value modified externaly

Question

onChange Event to be triggered if value modified externaly

80leaves opened this issue 11 years ago · comments

Hey,
I'm not quite sure if this is actually a "feature request" or a "bug". If I modify the value of the gpio-pin externaly, for example with gpio -g write 3 0 the onChange event is not triggered. If it is done via the nodeJS app it works fine.

Phil Coval · Answer 1 · Wed Jul 04 2018 19:04:40 GMT+0800 (China Standard Time)

I guess that would work for input gpio, for output I am not sure it can be know from outside context.

Dominick Pham · Answer 2 · Mon Oct 01 2018 09:47:52 GMT+0800 (China Standard Time)

Just confirming, we only watch for file changes with input direction. For the output direction, we emit the event as soon as we receive the call from the internal context. This saves on processing power by reading the value from sysfs at certain intervals.

I guess technically it's possible to watch for changes in the output direction, but it's outside the scope of this library. Filing as wontfix.