Question $9$

Suppose that we have Parentc and Child.c as follows. They are compiled and linked to generate the Parent and Child executable. Ireelow is Parentic

L$1$: tinclude ksyswalith:

L$2$: $*$cefine NULL $0$

$(3$: int main $($vold$)$

$14$:$1$

$15$: $,r(lork0)=0O$

$16$: printtCl am child process with PID: $\%d|n|=,$ getppld$())$:

$17.$ execrpr $\frac{?}{?}$ Child:NULL$)$;

L$11$: $,$ sleep$(5)$:

$112$: if$($wait$($NULU$)>0)$

L$13$: print$(["$Process$[$$d$]$: In$",$ getpid$(0)$;

$114$: print$("$Process$(\%$d$]$: $...$ In$",$ getppld$())$:

L$15$: $1$

$(16$:$)$

I$/$Below is Child.c

int main $($void$)$

$1$

$117$: printf$("$Process$[\%$d$]$: child in execution $...$tn$",$ getpid$())$;

L$18$: Sleep$(1)$;

$19$: printf$("$Process$[\%$d$]$: child terminating $...$n$",$ getppid$())$;

$120$: printf$("$HHHH:$\%$dn$",$ getpid$0)$:

$\}$

a What is the purpose of execyp $0$ at $L7?$

b How many times will the $HHH{H}^{**}$ at L$2$O be printed out? Please briefly explain.

CAt L$19,$ what process ID will be printed out by getppid$()?$ Note: no need to explain.