pub unsafe extern "C" fn fftw_plan_guru64_split_dft_r2c( rank: c_int, dims: *const fftw_iodim64, howmany_rank: c_int, howmany_dims: *const fftw_iodim64, in_: *mut f64, ro: *mut f64, io: *mut f64, flags: c_uint) -> fftw_plan