CPP CPP Interoperability & System Programming

Question 1

What is the primary purpose of extern "C" in C++?

Accepted Answer

To prevent name mangling so C code can link to C++ functions

Answer

To declare external global variables

Answer

To include C standard library headers

Answer

To disable C++ exception handling

Question 2

Which two techniques are commonly used to prevent multiple inclusions of a header file?

Accepted Answer

Both #pragma once and #ifndef/#define/#endif

Answer

#once only

Answer

#pragma once only

Answer

#ifndef/#define/#endif only

Question 3

When calling a C library that allocates memory, how must that memory be freed in C++?

Accepted Answer

Use free()

Answer

Use delete

Answer

Use delete[]

Answer

Use std::destroy

Question 4

What does the __cplusplus predefined macro indicate?

Accepted Answer

Whether code is compiled as C++ and which standard version is active

Answer

The CPU architecture being targeted

Answer

The compiler vendor name

Answer

Whether C++ exceptions are enabled

Question 5

What is C++ name mangling?

Accepted Answer

The compiler encoding of a function's full signature into its binary symbol name

Answer

Renaming variables at runtime for security

Answer

A technique to obfuscate source code

Answer

Renaming template parameters during instantiation

Question 6

How should a C++ function pointer be declared to be safely passed as a callback to a C library?

Accepted Answer

As a free function or static member with extern "C" linkage

Answer

As a lambda directly

Answer

As a std::function

Answer

As a virtual member function