Function set_kernel_default_config 

#[unsafe(no_mangle)]
pub extern "C" fn set_kernel_default_config(
    kernel: *mut CKernel,
) -> usize

because setting CKernel config can be annoying if you just want to do simple task , this function provides general config which will meet most of your needs . since v4.0.0 this function calls create_computing_gpu_resources automatically and assign its return value to config_index of your CKernel variable . only use this function once in your programs , instead of using this many times and causing memory leaks (well all that mem can be freed by free_compute_cache function) use config_index field of CKernel variable