search

warthog618 / gpio

A native Go library for Raspberry Pi GPIO
MIT License
124 stars 9 forks source link

panic: pin already in use #1

Closed indy99 closed 5 years ago

indy99 commented 5 years ago

no error on first run. when I cancel the program with ctrl-c getting this error. (Raspberry pi 3 B+)

err=pin.Watch(gpio.EdgeBoth, func(pin *gpio.Pin) { fmt.Printf("Pin 4 is %v\n", pin.Read()) }) if err!=nil { panic(err) }

defer pin.Unwatch()

panic: pin already in use

goroutine 1 [running]: panic(0xd2b10, 0x1040c198) /usr/lib/go-1.7/src/runtime/panic.go:500 +0x33c

warthog618 commented 5 years ago

I assume you are referring to the watcher example, or your code is drawn from that?

That example was deficient in that it did not check for errors (you added a check for that), nor guarantee to release resources (in this case the watched pin) if the process is killed. I have updated the example to do both, which should fix the issue.

Btw, you can manually clear the busy state that is causing the reported error in this case using

echo 4 > /sys/class/gpio/unexport

from a shell.

indy99 commented 5 years ago

echo 4 > /sys/class/gpio/unexport Probably somehow my GPIO pin has been keep open. After unexport it with your command, problem solved. Thank you.