Operation Modes

Question 1

According to your text, what are re-entrant messages?

Answer 1

messages your application receives while a blocking operation is outstanding

Question 2

According to the book, what is an advantage of threads?

Answer 2

you can create an application that handles many sockets simultaneously and uses blocking sockets

Question 3

According to the book, what is a disadvantage of threads?

Answer 3

Any program using them is not as portable to 16-bit Windows.

Question 4

What are the four types of timeouts for blocking operations?

Answer 4

automatic timeouts

user-settable timeouts

application timeouts

TCP keep-alive timeouts

Question 5

What are the three possible operation modes of Windows Sockets functions?

Answer 5

blocking, nonblocking, asynchronous

Question 6

What is meant by the term fake blocking?

Answer 6

Fake blocking means that although your application waits for the network operation to complete the WinSock DLL yields as you wait.

Question 7

What option is the default for closesocket() that blocks only if you have a blocking socket and set a nonzero timeout by calling setsockopt() to enable the SO_LINGER option?

Answer 7

SO_DONTLINGER

Question 8

Which socket functions time-out automatically, and are controlled completely by the network system?

a. connect, send, gethostbynature
b. connect, recv, gethostbyname
c. connect, send, gethostbyname
d. connect, recv, gethostbyagebyname

Answer 8

c. connect, send, gethostbyname

Question 9

Which Window Sockets operation mode, “transfers data quickly, yet remains friendly”?

a. all of them transfer data based upon the current weather conditions
b. Asynchronous
c. Non-Blocking
d. Blocking

Answer 9

b. Asynchronous

Question 10

What three functions can block forever and have no time limit?

Answer 10

recv(), recvfrom(), accept()

Question 11

What two functions allow an application to determine a timeout value?

Answer 11

select() and closesocket()

Question 12

__________mode is the “friendliest” but is relatively slow.

Answer 12

Blocking

Question 13

___________operation mode is the fastest, but requires the most overhead.

Answer 13

Nonblocking

Question 14

A Windows Sockets function returns only when the operation completes in _____________ operation mode.

Answer 14

blocking

Question 15

According to your text, which asynchronous function is considerd to be the most significant?

Answer 15

WSAAsyncSelect()

Question 16

What option can be set in setsockopt() to enable a timeout on a stream socket?

Answer 16

SO_KEEPALIVE

Question 17

True or False

A blocking function call returns immediately whether or ont the relevant network operation has completed.

Answer 17

False

Question 18

True or False

If a non-blocking socket function returns indicating there was success, it may not mean it did exactly what you asked.

Answer 18

True

Question 19

True or False

Non-blocking calls wait for operations to complete before returning to the calling application.

Answer 19

False

Question 20

True or False

A socket returned from the socket() function operates in nonblocking mode by default.

Answer 20

False