gpio permission denied

[Olejan]

I use this library on a OrangePi 3 LTS board. When I try to run blink example it works fine. But when I try to run isr-osc example I get this error:

gpio: Unable to open GPIO edge interface for pin 1: Permission denied
wiringPiISR: unable to open /sys/class/gpio/gpio121/value: No such file or directory

If I run isr-osc example with root I get same error

sudo ./isr-osc

What is the promlem?

[borex99]

Same as #98.
#101 should fix this error.