Simon Willison’s Weblog

Thread Synchronization Mechanisms in Python. Locks, RLocks, Semaphores, Events and Conditions as explained by Fredrik Lundh.

Posted 29th July 2007 at 9:32 pm

Recent articles

Video + notes on upgrading a Datasette plugin for the latest 1.0 alpha, with help from uv and OpenAI Codex CLI - 6th November 2025
Code research projects with async coding agents like Claude Code and Codex - 6th November 2025
A new SQL-powered permissions system in Datasette 1.0a20 - 4th November 2025

conditions 1 effbot 4 events 108 fredrik-lundh 7 locks 1 python 1204 rlocks 1 semaphores 1 threads 18 tutorial 18

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