cx-ifstream-hot — measured, still hint
Status
hint. Wall-clock JSONL: cx-ifstream-hot.jsonl. Not corpus-triaged. The 2026-10-22 corpus verdict does not cover this slug.
Measurement
std::ifstream of one one-byte file, 2000 times, versus opening once. Both sides read one byte. This does not revive removed CX003.
| role | case | median_ms | ops | ratio |
|---|---|---|---|---|
| after | open_once | 0.00725 | 2000 | 1 |
| before | open_each_iter | 14.6835 | 2000 | 2025.32 |
The bench reopens one one-byte file. A path that changes every iteration cannot be hoisted. Default stays hint. 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.