Closures as Win32 window procedures

262 · Christopher Wellons · Dec. 12, 2025, 8 p.m.
Summary
This blog post discusses the use of closures in Win32 window procedures to pass additional context using a fifth argument. The author revisits a technique for enhancing window procedure callbacks with a new context pointer through trampoline functions. The article details the process of creating a trampoline for custom allocation and provides practical examples and assembly code to illustrate the technique, highlighting its applications in software development.