Need a sleep/timeout after exporting pin? about rust-sysfs-gpio HOT 4 CLOSED

Thanks for filing the issue. I tested mostly on the BBB and RPi 1 and may have been running as root (I don't recall). My expectation is that the export would be a synchronous operation, but you clearly have some evidence to the contrary. Maybe changing of permissions is handled outside of the kernel by something like udev? I'll have to research a bit more.

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You are right, permissions are changed by udev, the rules are in /lib/udev/rules.d/60-python3-pifacecommon.rules and /lib/udev/rules.d/60-python-pifacecommon.rules files.

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Ok, given that this is udev, I think I will update the example for greater compatibility and add a comment to the code stating that you may need a delay (or to poll for appropriate stat on some file). I don't think a change to the library core to add a delay would be appropriate as many systems would not be setup in the same way.

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I agree that this library should not need to handle delays caused by udev.

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