And you risk a collision for global identifiers, which cannot be reorganized in C. If some library had the same thought and defined `mkdir` first, your code can

And you risk a collision for global identifiers, which cannot be reorganized in C. If some library had the same thought and defined `mkdir` first, your code can't define `mkdir` even as a private symbol. So you have to prefix everything and that contributes to the identifier length. In comparison, Go has a much better (but personally not yet satisfactory) module system and can have a lower limit.