[libgpiod] reading multiple lines after edge event

[Gerrit Wyen <ml@xxxxxxxxxxxx>]

Hi,

can someone explain the following behavior and whether it is a bug?

When reading two lines at once via get_values() in response to an edge 
event I only receive the correct value for the first line (second line 
is high during the test but always reported as low).
See example code below:

lines.request({
 “gpiotest”, ::gpiod::line_request::EVENT_BOTH_EDGES,
 0,
});

auto events = lines.event_wait(::std::chrono::seconds(10));
if (events) {
 auto values = lines.get_values();
 for (auto& it: values) {
   ::std::cout << it;
   }
 }

However reading the same lines via get_value() one by one after the 
event works correctly. Like so:

for (auto& it: lines) { ::std::cout << it.get_value(); }


Also, when reading them without waiting for the event with 
line_request::DIRECTION_INPUT  the correct values are returned by 
get_values() as well as by get_value().

This behavior was tested on multiple different devices.


thanks,

Gerrit