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Python Basic Usage Sample

Purpose and Audience

This sample is the smallest Python consumer of the installed shared-memory-store wheel. It demonstrates Python context managers and borrowed memoryview lifetimes over the wheel's adjacent C ABI 2 native library.

Concepts Demonstrated

  • participant-aware StoreOptions.create;
  • immutable SMS2 layout, resource protocol, feature, and participant identity;
  • MemoryStore.open and context-managed close;
  • opaque payload and descriptor bytes;
  • a context-managed lease with borrowed read-only views;
  • remove and diagnostics; and
  • loading the packaged native library rather than repository sources.

Prerequisites

  • Python 3.10 or newer on a qualified x86-64 Windows or Linux host.
  • An installed shared-memory-store 1.0.0 platform wheel.
  • The wheel's adjacent native library with C ABI 2.0.

Run

From the repository root, using the clean wheel environment:

artifacts/python-consumer/Scripts/python samples/PythonBasicUsage/main.py

Use artifacts/python-consumer/bin/python on Linux.

Expected Output

protocol=SMS2 layout=2.0 resource=2 required=0x7 optional=0x0 participants=4
value=b'hello from Python\x00' descriptor=b'sample'
free slots: 2/2

Expected Non-Success Statuses

  • UNSUPPORTED_PLATFORM: mapped atomics or required platform facilities are unavailable.
  • INCOMPATIBLE_LAYOUT: an existing mapping is not canonical SMS2.
  • PARTICIPANT_TABLE_FULL: every participant record is occupied.
  • STORE_BUSY: a bounded cold-open or local progress budget expired.

Unexpected results raise an exception and produce a nonzero process exit.

Cleanup

The sample uses a unique name, closes its lease, removes the value, and closes the store through context managers.

Related Documentation

Scope Boundaries and Non-Goals

Run this against an installed wheel. Adding src/python to PYTHONPATH does not supply the adjacent packaged native library and is not a package-consumer test. This sample does not implement the mapped protocol in Python.