[cffi-devel] How to define a pointer to a 2d array

I have a function that accepts a  void* as a parameter Im trying to convert this to use as the void* float trainingData[4][2] = { {501, 10}, {255, 10}, {501, 255}, {10, 501} }; this is how i do a void* 1d array   float labels[4] = {1.0, -1.0, -1.0, -1.0}; (labels (foreign-alloc :float :initial-contents '(1.0 -1.0 -1.0 -1.0))) so how  do i do the 2d array