LanguagesCEvidence
cp-sprintf-hot — measured, still hint
Status
hint. Wall-clock JSONL: cp-sprintf-hot.jsonl. Not corpus-triaged. The 2026-10-22 corpus verdict does not cover this slug.
Measurement
100000 iterations at clang -O2. Before calls sprintf into a stack buffer; after writes decimal digits into the same buffer. The input is the loop index.
| role | case | median_ms | ops | ratio |
|---|---|---|---|---|
| after | digits_into_buffer | 0.543000 | 100000 | 1 |
| before | sprintf_in_loop | 7.553000 | 100000 | 13.910 |
The microbench shows a cost for this one shape. Default stays hint until the shape is corpus-triaged. This ratio is not a general speedup.
Unblock
Do not set the default to error from this file alone. A changing input, a cold path, or another ABI can erase the difference. Corpus triage is still required before any default change.