2.4 APUE07-10

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

if (pid=fork()) {fork();}

if (pid=fork()) {fork();}

if (pid=fork()) {fork();}

---

• 8

• 9

• 16

• 27

• 32

27

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

if (fork()) {fork();}

---

• 1

• 2

• 3

• 4

• 0

3

After fork, the return value for the child is ___

---

• -1

• 0

• 1

• a new process ID for the child process

• the process id of the parent process

0

By convention, UNIX System shells associate the file descriptor __ with the standard input of a process.

---

• 0

• 1

• 2

• 3

• -1

0

After fork, the differences between the parent and child are ____.

---

• The return values from fork

• The process IDs

• The different parent process IDs

• All of the above

• None of the above

All of the above

A file ___ is normally small non-negative integer that the kernel uses to identify the files accessed by a process.

---

• buffer

• table

• descriptor

• i-node

• entry

descriptor

By convention, all shells in Unix open ___ file descriptors whenever a new program is run.

---

• 0

• 1

• 2

• 3

• 4

• as many as needed

3

Consider a code segment for a pipe (e.g., to run "ls | wc") as we discussed in the classes, shown below.

What would it be the code segment using execlp for the "parent" process after setting the file descriptors for the pipe?

---

• execlp("ls","ls",(char *)0);

• execlp("wc","wc",(char *)0)

• execlp("ls","wc",(char *)0)

• execlp("wc","ls",(char *)0)

• execlp("ls | wc",(char *)0)

execlp("ls","ls",(char *)0)

Signals provide a way of handling ___ events

asynchronous

If a process needs a child process to do some of its work, it will call ___ to make a copy of the current process.

---

• dup

• clone

• thread

• fork

• dup

fork

After fork, the return value for the parent process is ___

---

• -1

• 0

• 1

• the child process id

• the process id of the parent process

the child process id

What would be a proper way to set a signal handler (sig_int) for SIGINT?

---

• SIGINT(sig_int);

• sigint(SIGINT);

• SIGINT(signal, sig_int);

• signal(SIGINT, sig_int);

• signal(sig_int, SIGINT);

signal(SIGINT, sig_int);

The new process created by fork is called the child process. This function is called once but returns ___.

---

• none

• once

• twice

• three times

• as many as needed

twice

Given fork program as shown below, what would be the total number of processes at the end including the process running this program.

for (i=1; i < nprocs; i++) { childpid = fork(); }

When nprocs = 3, then the total number of processes after this code will be ____

---

• 1

• 2

• 4

• 8

• 16

4

For convenience, ___ call is used to execute a command string (e.g., "ls -la | wc") within a program.

---

• thread

• process

• pipe

• fork

• system

system

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

fork(); fork(); fork();

---

• 1

• 4

• 6

• 8

• 16

8

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

if (fork() < 0) {fork();}

---

• 1

• 2

• 3

• 4

• 0

2

The new file descriptor returned by dup is guaranteed to be the ___ numbered available file descriptor

---

• lowest

• highest

• fixed

• stack

• arbitrary

lowest

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

if (pid=fork() && pid2 = fork()) {fork();}
if (pid=fork() && pid2 = fork()) {fork();}
if (pid=fork() && pid2 = fork()) {fork();}

---

• 16

• 27

• 32

• 48

• 64

64

Which API call completely replaces the current process with a new program (text, data, heap, stack)?

---

• fork

• system

• exec

exec

The ____ contains all the information about the file: type, permissions, size, data pointers, etc.

---

• v-node

• i-node

• file descriptor

• superblock

• directory

i-node

For a pipe (ls | wc), what does the parent do after fork but before exec?

---

• close(pfd[0]); dup2(pfd[1], 1); close(pfd[1]);

• close(pfd[1]); dup2(pfd[0], 0); close(pfd[0]);

• close(pfd[0]); dup2(pfd[0], 1); close(pfd[1]);

• close(pfd[1]); dup2(pfd[1], 0); close(pfd[0]);

close(pfd[0]); dup2(pfd[1], 1); close(pfd[1]);