Function xt_set_callback 

pub unsafe fn xt_set_callback(
    plan: cufftHandle,
    cb: *mut c_void,
    cb_type: CufftXtCallbackType,
    caller_info: *mut c_void,
) -> cufftResult

Install a load/store callback on a cuFFT plan.

cb must point to a CUDA device function with the signature matching cb_type (see the cuFFT docs). caller_info is passed straight through to the device callback at call time.

Returns CUFFT_NOT_SUPPORTED if libcufft couldn’t be opened or doesn’t export cufftXtSetCallback (older toolkits before the Xt API was carved out). All other return codes are passed through.

Safety

• plan must be a live cuFFT handle.
• cb must point to a device-resident function with the appropriate signature.
• caller_info must outlive every kernel launch on plan.