pub unsafe extern "C" fn fftwf_plan_dft_r2c(
rank: c_int,
n: *const c_int,
in_: *mut f32,
out: *mut fftwf_complex,
flags: c_uint,
) -> fftwf_plan
pub unsafe extern "C" fn fftwf_plan_dft_r2c(
rank: c_int,
n: *const c_int,
in_: *mut f32,
out: *mut fftwf_complex,
flags: c_uint,
) -> fftwf_plan