Written Assignment 8

The following answer assumes printf() will print immediately in stdout with no buffering like sio_printf() as suggested in piazza.

Question 1

a. there are 2 possible outputs

1. pikachu
2. kapichu

b. there are 3 possible outputs

1. kapichuchu
2. pikachuchu
3. pichukachu

Question 2

a. There are 8 different output sequence (signal might not receive before exit(0) for children)

A possible sequence can be:

count = 1
count = 2
count = 3

b. Will be different. An example can be:

count = 1
count = 1
count = 2
count = 2
count = 3
count = 3

Question 3

man sigprocmask, gives the following:

The behavior of the call is dependent on the value of how, as follows.

       SIG_BLOCK
              The set of blocked signals is the union of the current  set  and
              the set argument.

       SIG_UNBLOCK
              The  signals  in set are removed from the current set of blocked
              signals.  It is permissible to attempt to unblock a signal which
              is not blocked.

       SIG_SETMASK
              The set of blocked signals is set to the argument set.

Therefore, three possible values and their corresponding behavior are:

• SIG_BLOCK: adding the set to block mask. Therefore, everything in the set will be blocked, and everything not in set will remain its status.

• SIG_UNBLOCK: removing the set from block mask. Therefore, everything in the set will be unblocked, and everything not in set will remain its status.

• SIG_SETMASK: everything in the set will be blocked and everything not in the set will be unblocked.