Lucas Nussbaum: System calls quizz

1. What is special about the socket, connect, bind, accept, … system calls?
2. How does the errno value get from the kernel to applications?
3. Some system calls return a number of times different of 1 in some cases. Which ones? (Put differently: enter a syscall once, exit more or less than once. Which ones can do that?)

(Thanks MG!)