What is std::async with launch policies?
PICTURE THIS: ASYNC / PROMISE
Simple meaning
async may run deferred or on another thread depending on policy.
WHY — Concurrency instead of guessing?
Why interviewers care about Concurrency:
who only read docs from people who shipped.
and tied to C++ work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1async may run deferred
or on another thread depending on policy.
- 2Why it exists
Deferred runs lazily on get.
- 3I set policies explicitly
to avoid surprises.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
async may run deferred or on another thread depending on policy. Deferred runs lazily on get.