How to keep the pin's value about c-periphery HOT 5 CLOSED

No worries. Feel free to open an issue if you have any other questions or problems.

from c-periphery.

Hi @yyykkkyyy. It sounds like your program is terminating after the gpio_write()? If you are using character device GPIOs, e.g. with a /dev/gpiochipN device, you should keep in mind that the GPIOs won't retain their output state and will revert to a default state (likely an input) after being released when the program exits.

from c-periphery.

Thank you for your replying @vsergeev !!
Yeah, as you mentioned above, I use /dev/gpiochipN char device.
And I use the sample code which is on the README.

If you are using character device GPIOs, e.g. with a /dev/gpiochipN device, you should keep in mind that the GPIOs won't retain their output state and will revert to a default state (likely an input) after being released when the program exits.

Is this behavior the specification of /dev/gpiochipN?
Can I retain the GPIO's state ?

from c-periphery.

Yeah, that's the behavior of the Linux character device GPIO API. You can retain state after close with the sysfs GPIO API if you export the GPIO before c-periphery opens it (gpio_open_sysfs()), but the Linux sysfs GPIO API is deprecated and will be removed in future versions of Linux.

from c-periphery.

Oh, Okay. I understood the behavior !
In fact, I used the sysfs GPIO but I knew it will be deprecated. So I explore the other way.
Thank you very much @vsergeev !!!
And sorry for my poor English :-)

from c-periphery.