Recitation 13: Solutions

Fork & Signals

Question 1

Outputs:

• 32040 - This is a possible output.
• 34002 - N
• 30402 - Y
• 23040 - Y
• 40302 - N

As long as 30 is printed before 40, the output is possible. The 2 can be pretty much anywhere.

Question 2

Answers:

Part I

• 1 - 10 times
• 2 - The value is 1
• 3 - The value is 2

Part II

counter = 1

counter = 3

counter = 3

Part III

• 1 - No, it is different
• 2 - counter = 1,2,3,4,5 (1 is also possible - this would happen if all child processes termintated before the control was returned to the parent process; when the parent process runs the handler, the value is incremented to 1 and then no more child processes would terminate to cause the handler to run again)

Question 3

Output:

Hello 0 1 Bye 2 Bye

OR

Hello 1 0 Bye 2 Bye

Question 4

• a) 8
• b) 3
• c) 5
• d) counter = 2

Question 5

Answer: val = 15