Function pxs_object_addfunc 

#[unsafe(no_mangle)]
pub extern "C" fn pxs_object_addfunc(
    object_ptr: *mut pxs_PixelObject,
    name: *const c_char,
    callback: pxs_Func,
    opaque: pxs_Opaque,
)

Add a callback to a object.