Hello_gpio_irq example


I’ve been trying to get the C++ hello_gpio_irq example in the pico-examples project to work on a Pico Explorer Base (I’m guessing the same might be true of the Pico Display Pack). If I set the GPIO to 16 (sw_a) from 2 in the example in the gpio_set_irq_enabled_with_callback call (although I’ve read that this is ignored anyway) I get no output whatsoever when I press any of the four Pico Explorer Base’s buttons.

The reason I am trying to do this is I need the buttons to work on interrupts rather than using
if (pico_explorer.is_pressed(pico_explorer.A)) in a tight loop as I need it to work during sleeps.

Is there something I am missing here?