If you do that your program probably does more than just call what you're saying the program does. This is like someone saying they wrote a one line memory allocator and calling mmap or saying you wrote a one line video converter that just calls ffmpeg.
Even if you're writing a kernel, you're using a compiler. And if you're writing a compiler it's probably bootstrapped and built by itself, so you're still using a mountain of code some other people wrote. :)
