CS 3733 Operating Systems, Spring 2009 Diagnostic Exam 1 Comments

• ret is an integer variable.
  It cannot contain a string.
• NULL prepresents a pointer value.
  It should not be used for integer variables.
• Read the questions and answer what is asked.
  You should know what is meant by the word list.
  
• It is not an error if read or write return a value less than what is asked as long as the value is not -1.
  See your answer to question 3.
• Sometimes you need to take action, even if no error is produced, for example, in b) when the return value is 1.
• In a), the return value might be 1 and this i what you want.
  

1. 1. -1, 0, 1, 2 or 3.
   2. -1, 1, or 2.
2. 1. 0, 1, 2 or 3.
   2. 1, or 2.
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.