fatal error: cannot open file – does awk flush output when interrupted by SIGINT?

Goal

Investigate whether GNU Awk flushes partially written data to stdout or output files when it receives a cancellation signal such as SIGINT. The documented error string "fatal error: cannot open file" is used as a reliable anchor for parsing error logs, but it does not describe signal handling behavior.

Constraints and Uncertainty

Awk has no built‑in timeout mechanism; external utilities like timeout or shell traps are required to stop long‑running scripts. POSIX does not specify how awk should behave on signal delivery, and implementations differ: some terminate immediately without flushing, while others may ignore the signal unless explicitly handled. The lack of a documented graceful‑shutdown API leaves data integrity uncertain in pipelines that rely on complete output.

Unresolved Questions

• When awk is terminated by SIGINT, does it automatically flush any data remaining in its output buffers to stdout or open files?
• If not, what mechanisms (e.g., external traps, custom BEGIN/END blocks) can reliably guarantee that all processed records are written before termination?
• Is there any configuration or signal‑handling extension available in recent GNU Awk releases that allows a graceful shutdown on cancellation?