Coordinate Basic Threads and Inspect Them on Linux

Explain how to invoke a supplied function concurrently using basic thread APIs, manage the threads' lifecycle, and inspect the process's threads on Linux. Higher-level process pools, thread pools, and asyncio are not allowed for this exercise.

Constraints & Assumptions

• The source permits Python or C++ and specifically names basic threading APIs. Use Python's threading primitives for this practice version; do not use ProcessPoolExecutor, ThreadPoolExecutor, or asyncio.
• Practice scope: a finite list of independent work items is supplied to a callable. Invoke it once for each item, use a bounded number of manually created worker threads, retain a result or exception for each input position, and wait for all started threads before returning.
• The source does not reveal the callable's behavior or the later interview parts. Do not invent those requirements.
• Clarify whether the callable is thread-safe, whether it blocks on I/O, and whether concurrent invocation is permitted. Do not assume threads always speed up CPU-bound Python code.

Clarifying Questions to Ask

• Can two calls share or mutate state, and which component is responsible for synchronization?
• Should one failed call stop future work or should the remaining items continue?
• Are results required in input order or completion order?
• Can the callable cooperate with cancellation, and can a call block indefinitely?

Part 1 — Coordinate Basic Threads

Describe thread creation, work assignment, result collection, and joining for the practice scope. Explain which shared state needs synchronization and what happens when a call raises an exception.

What This Part Should Cover

• Bounded manual Thread creation and exactly-once assignment of input positions within one invocation.
• Short critical sections around shared coordination, with the supplied function called outside the assignment lock.
• Explicit exception capture, deterministic result indexing, and joining non-daemon workers.

Part 2 — Inspect Threads on Linux

Give commands that list a process's threads and show per-thread activity. Explain how to relate operating-system thread IDs to application diagnostics and distinguish observation from proof of correctness.

What This Part Should Cover

• Process ID versus Linux thread ID, and suitable thread-list or live-inspection commands.
• Native thread identity and names in application logs.
• The limits of CPU usage and thread-state snapshots when diagnosing deadlock, waiting, or a slow callable.