add_once

Adds a function to be called whenever there are no higher priority events pending to the default main loop.

The function is given the default idle priority, [const@GLib.PRIORITY_DEFAULT_IDLE].

The function will only be called once and then the source will be automatically removed from the main context.

This function otherwise behaves like [func@GLib.idle_add].

Parameters:

function	function to call
data	data to pass to function

Returns:

the ID (greater than 0) of the event source