SOP k1 05 2

}

for(i = 1; i < 4; i++) if (wait(0) == -1) {

perror("Error in wait"); return 1;

return 0;

3. (10 p.) You are given a program:

int main ()

{

pid_t pid; int i;

for (i = 4; 1++)-

switpłf^Cpid = fork()) { case -1:

perror("Error in fork"); return 1; case 0:

execlp("pwd","pwd",0); perror("Error in exec^M); exit(1) ; default:

printf("pid = %d", pid);

Mark correct answers (correct answer is worth +2p, while incorrect answer yields

—2p.

(a) The program creates:

i. a linę of processes (father, son, grandson etc.),

ii. a bunch of processes (father and a number of sons),

iii. a treę of processes,

iv. one ęhild process.

(b) The program creates:

i. /l child process,

ii. 3 child processes,

iii. 4 child processes,

iv. 7 child processes.

i. Yes

ii. No

(d) Which processes output their identi-fiers?

i. the parent process,

ii. the child process(es),

iii. both,

iv. nonę.

(e) The parent process:

i. does not wait for the termina-tion of its children,

ii. waits for the termination of all its children,

iii. waits for the termination of one child (but not all).