Question

- Question 3. [25 marks] Consider the execution of the following function (written in the C language). void test() { int a=1; fork(); a=a+2; if (fork()==0) H a=2*3;4 printf("la: %d\nma); 3(a) Draw the process graph for the execution of “test”. [10 marks] 3(b) Give an example of infeasible output of “test”. Explain why it is infeasible output. [8 marks] 3(c) The output of “test” depends on the scheduling of processes on CPU. There can be many feasible output of “test”. V Calculate the number of feasible output of “test”. Show your steps. [7 marks]

Answer 1

3a void test) as! P3 torki); a: 3 if(fork) :-) if (togels--0) asa* 3 1 La 9. اما =) a=9. Pf(la:)? Printf(la : 73. forked will create a child value o ра to child process process and Р. 1 & positive value to parent process. a=1 a=2+2) 0-3 Pa ve 4 forke) ==0) it froko) ==0) Pfl laia) - La: 3 ci za 3 a) 9. 36) 3999. 44 30) are Pf(Laia) Laig The in feasible output is Because here only (fork() ==0) will be True only for them. the last 2 child process will have value of a=9 since There process created including the main роем. 아 a as 3 and remaining two will print value of a as a since for them is the if condition (forke) = o) wolds true.' So total we have 4 print statement executing. Any of execute process Istatement first print of output = 21*2} The two ralue process prints the so total 41 # since 349 are repeated twice.

note: Output 3 9 9 9 means

La:3

La:9

La:9

La:9

All the statement inside printf will be printed exactly.