Function pio_dc_opf_preparation_reference_buses 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn pio_dc_opf_preparation_reference_buses(
    preparation: *const PioDcOpfPreparation,
) -> PioSizeView

Borrow the dense reference bus indices of a DC OPF preparation.

Safety

Pointers and handles must satisfy the crate-level safety requirements.