Gets the hardware ID of this tool, or 0 if it's not known. When
non-zero, the identificator is unique for the given tool model,
meaning that two identical tools will share the same @hardware_id,
but will have different serial numbers (see gdk_device_tool_get_serial()).
This is a more concrete (and device specific) method to identify
a #GdkDeviceTool than gdk_device_tool_get_tool_type(), as a tablet
may support multiple devices with the same #GdkDeviceToolType,
but having different hardware identificators.
Gets the hardware ID of this tool, or 0 if it's not known. When non-zero, the identificator is unique for the given tool model, meaning that two identical tools will share the same @hardware_id, but will have different serial numbers (see gdk_device_tool_get_serial()).
This is a more concrete (and device specific) method to identify a #GdkDeviceTool than gdk_device_tool_get_tool_type(), as a tablet may support multiple devices with the same #GdkDeviceToolType, but having different hardware identificators.
Return: The hardware identificator of this tool.