can a request be used after gpiod_chip_close() in v2.x ?

[mfide]

Hello,

I start trying to understand how this library (v2.x) works, go through examples and documentations.

In reconfigure_input_to_output.c example:

1. It configures a pin to be input in the request_input_line function. But then closes the chip before returning.
2. Later in the main the request from above function used for the rest of the example while the chip is already closed.

Is this correct usage? Then it means I don't need to keep chip open for the lifetime of my application?

Thanks.

[brgl]

Yes, the request object can live independently from the parent chip.

[mfide]

Thank you for the confirmation, this is valuable input for my design.
However, I recall reading somewhere that when the chip is closed, all related resources are freed and the GPIOs return to their default state. Is that not the case?

[brgl]

Yeah, I sometimes take mental shortcuts resulting in me not being clear enough. "Closing the chip" means dropping all references to it by calling close() on all the file descriptors associated with the character device. That means the fds obtained by opening the chip as well as the ones resulting from making requests on the chip's fd. Also: a released line does not return to its "default" state, there's no such thing. Its state is effectively unknown.