How do you speed up large C++ builds?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
Precompiled headers, fewer includes via forward declares, unity builds carefully, and caching like ccache.
WHY — Build instead of guessing?
Why interviewers care about Build:
question about Build.
trade-offs, and what you would actually do on a C++ project - not buzzwords.
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:
- 1Precompiled headers, fewer includes
via forward declares, unity builds carefully, and caching like ccache.
- 2Modules help when the
toolchain is ready.
- 3How it works
I measure with ninja timing.
- 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
Precompiled headers, fewer includes via forward declares, unity builds carefully, and caching like ccache. Modules help when the toolchain is ready.