Function func_attributes 

pub unsafe fn func_attributes(
    func_symbol: *const c_void,
) -> Result<cudaFuncAttributes>

Query a kernel’s register / shared-memory / PTX-version metadata. func_symbol is a const void* — the address of the kernel symbol as used by cudaLaunchKernel (or crate::Kernel::as_launch_ptr).

Safety

func_symbol must be a valid CUDA kernel symbol address. Passing garbage causes undefined behavior inside the driver.