PCPP2 Interprocess Communication Practice Test 2 — 15 Questions

Question 1

Which module allows you to run external programs and interact with their input/output streams?

Accepted Answer

subprocess. The subprocess module is the recommended way to spawn new processes and connect to their pipes.

Answer

sys

Answer

multiprocessing

Answer

os

Answer

threading

Question 2

Which of the following is true regarding daemon threads in Python?

Accepted Answer

They are abruptly terminated when the main process exits.. Daemon threads are terminated abruptly when the main program exits, which can lead to incomplete operations.

Answer

They are only used for system-level tasks.

Answer

They are guaranteed to finish before the program ends.

Answer

They use more memory than regular threads.

Answer

They cannot create child threads.

Question 3

You are using Pool.apply_async(). How do you retrieve the result of the function call?

Accepted Answer

Call the get() method on the returned object.. The apply_async method returns an AsyncResult object, and you must call the get() method on it.

Answer

Wait for the function to return.

Answer

Use the join() method on the pool.

Answer

Pass a callback function.

Answer

Check the pool's result list.

Question 4

If you want to run a function in a background thread, which class should you instantiate?

Accepted Answer

threading.Thread. The threading.Thread class is the standard way to create threads.

Answer

threading.Process

Answer

subprocess.Thread

Answer

multiprocessing.Thread

Answer

thread.Task

Question 5

What is the result of using a Pipe to communicate between two processes if both processes attempt to write to the same end simultaneously?

Accepted Answer

The data may be corrupted or interleaved.. Data corruption can occur as the messages may become interleaved or mangled.

Answer

It raises an exception.

Answer

The OS serializes the writes automatically.

Answer

The write blocks until the other finishes.

Answer

One of the writes is silently dropped.

Question 6

What is the primary purpose of the subprocess.PIPE constant?

Accepted Answer

To create a channel for data transfer.. It is used to indicate that a new pipe to the child process should be created for stdout or stdin.

Answer

To terminate the child process.

Answer

To speed up subprocess execution.

Answer

To close the standard input.

Answer

To redirect output to a file.

Question 7

Which TWO of the following are valid ways to synchronize threads?

Accepted Answer

threading.Semaphore. Locks and Semaphores are fundamental threading synchronization primitives.

Answer

threading.ProcessPool

Answer

threading.Queue

Answer

threading.Process

Question 8

When using the multiprocessing module, why is it recommended to use a Manager object instead of a standard dictionary to share data between processes?

Accepted Answer

It ensures the dictionary is synchronized between processes.. A manager process is created to host the objects, allowing them to be shared safely between different processes using proxy objects.

Answer

It is faster than standard dictionaries.

Answer

It is the only way to store strings.

Answer

It removes the need for locks.

Answer

It allows local storage of values.

Question 9

Which TWO of the following are key benefits of using the multiprocessing.Pool class?

Accepted Answer

Automatic process creation and management.. Pools simplify process management and provide convenient result retrieval mechanisms.

Answer

Higher performance for I/O tasks than threads.

Answer

Guaranteed memory sharing between processes.

Answer

Automatic elimination of the GIL.

Question 10

Which of the following describes the difference between Process.terminate() and Process.kill()?

Accepted Answer

Terminate() sends SIGTERM, while kill() sends SIGKILL.. On most POSIX systems, terminate() sends SIGTERM (polite), while kill() sends SIGKILL (immediate).

Answer

There is no difference.

Answer

Terminate() is for threads.

Answer

Terminate() is more immediate than kill().

Answer

Kill() is only available on Windows.

Question 11

Which TWO of the following are true about the multiprocessing.Queue object?

Accepted Answer

It is safe to use between processes.. Queues are thread-safe and process-safe, and they use internal locks and pipes.

Answer

It allows direct memory access between processes.

Answer

It is slower than a standard Python list.

Answer

It requires an external database to function.

Question 12

Which TWO of the following scenarios are best suited for the subprocess module?

Accepted Answer

Running an external C++ executable.. Subprocess is intended for executing external binaries and interacting with their system streams.

Answer

Sharing memory between Python threads.

Answer

Managing internal thread pools.

Answer

Parallelizing Python functions.

Question 13

Which THREE of the following are valid ways to instantiate a process in the multiprocessing module?

Accepted Answer

By subclassing multiprocessing.Process.. Process can be instantiated directly, via target function, or by subclassing.

Answer

Using the multiprocessing.Queue method.

Answer

Using the threading.Thread class.

Question 14

Which TWO of the following are potential issues when using the 'fork' start method in multiprocessing?

Accepted Answer

Threads present in the parent may not be safe in the child.. Forking a process inherits the parent's memory, which can lead to issues with locks and threads.

Answer

It cannot share data at all.

Answer

It crashes on all Unix systems.

Answer

It is always slower than spawn.

Question 15

Which THREE of the following represent types of IPC provided by the multiprocessing module?

Accepted Answer

Pipe. Multiprocessing provides Pipes, Queues, and Managers for inter-process communication.

Answer

Thread

Answer

Global