IIFE (Immediately-Invoked Function Expression) is a technique in C++ that uses lambdas to initialize const variables with complex multi-line logic. Instead of dropping const and writing mutable initialization code inline, you wrap the logic in a lambda and immediately call it. The post covers syntax, readability improvements via named lambdas or std::invoke(), capture list best practices (prefer explicit captures over [&]), a C++26 update that allows omitting empty parentheses, a practical HTML string-building example, and a benchmark showing ~10% performance gain from increased const usage.
Table of contents
IntroIIFEImproving Readability of IIFEShould we capture the whole context with & ?C++26 UpdatesUse Case of IIFEA Benchmark of IIFESummaryReferences and BooksSort: