C++ interview questions and answers

Use pimpl, C interfaces, or carefully versioned shared libs.

Link-time optimization analyzes across translation units.

Priority inheritance locks or design so low priority holders do not block high priority long.

Friend functions defined inside a class only found via ADL.

Share until write, then detach.

It constrains templates with boolean conditions or concepts.

Use Benchmark libraries, warm up, pin frequency when possible, and avoid dead-code elimination surprises.

Idle threads steal tasks from busy threads’ queues.

Push free nodes with atomics or under lock.

Enable newer standards per target, fix breakages, adopt span and constexpr where safe.

Place rare paths out of line so hot paths stay compact in I-cache.

Directly selecting the Nth pack element improves metaprogramming clarity.

new can throw bad_alloc

Readers retry if a writer sequence changed mid-read.

Multi-dimensional span over contiguous data with layouts.

Atomic operations or a mutex around the critical section.

RAII, commit-or-rollback order, and strong guarantee where needed.

Favor contiguous data, smaller structs, and access in order.