There remains at least one area in the Ada bindings which is still affected by the C underpinnings. This might be cleaned up in future versions. There might be other residual C influence as well.
plmapform as called by Draw_Latitude_Longitude (plmap) and Draw_Latitude_Longitude (plmeridians)
This is the only place in the PLplot bindings where a C subprogram calls an Ada subprogram while passing an array. If the array is unconstrained, there is no guarantee that it will work because C has no way of telling Ada what offset to use for the beginning of the array. But passing a constrained array is acceptable with the downside that the array size must be fixed within the bindings as being large enough to handle any situation; currently, it is sized as 0 .. 2000. See Example 19 for how this is handled in by the user program. The constrained array is called Map_Form_Constrained_Array.