CS 3733 Operating Systems, Spring 2009 Diagnostic Exam 2 Comments

• The main difference between this exam and the previous one is that small writes to a pipe are atomic. This is not true for reads.
• If you attempt to write fewer than PIPE_BUF bytes, it will either all succeed or it will fail.
• PIPE_BUF is always at least 256.

1. 1. -1, 0, 1, 2 or 3.
   2. -1 or 2.
   Small writes to a pipe are atomic. Reads are not.
2. 1. 0, 1, 2 or 3.
   2. 2.
   Small writes to a pipe are atomic. Reads are not.
3. In either case an error occurs if the return value is -1.
   In this case an error message can be displayed using perror or gotten using strerror and errno.