Function gdk4_sys::gdk_popup_layout_get_shadow_width

pub unsafe extern "C" fn gdk_popup_layout_get_shadow_width(
    layout: *mut GdkPopupLayout, 
    left: *mut c_int, 
    right: *mut c_int, 
    top: *mut c_int, 
    bottom: *mut c_int
)

This is supported on crate feature v4_2 only.