Function get_convolution_forward_algorithm 

pub unsafe fn get_convolution_forward_algorithm(
    handle: cudnnHandle_t,
    src: cudnnTensorDescriptor_t,
    filter: cudnnFilterDescriptor_t,
    conv: cudnnConvolutionDescriptor_t,
    dest: cudnnTensorDescriptor_t,
    requested_algo_count: c_int,
    returned_algo_count: *mut c_int,
    perf_results: *mut cudnnConvolutionFwdAlgoPerf_t,
) -> Result<(), CudnnError>

See nvidia docs

Safety

• All handles & descriptors must still be allocated.
• The pointers must point to valid memory.