Hi Matti, On 14 June 2014 23:54, Matti Picus <matti at picus.org.il> wrote: > 2. how can ctypes2lltype(Unsigned, 784L) fail? Shooting in the dark, maybe running multiple tests in parallel caused interference which meant that 'rffi.platform.numbertype_to_rclass' is incompletely populated? Armin