std::launch(3)

💖 NAME 💖

okay bestie, this is std::launch(3) from the C++ Standard Libary — and the NAME line is literally std::launch - std::launch. No cap, that’s the whole vibe 💅.

🦋 Synopsis 🦋

It’s defined in the header <future>, and here’s the synopsis exactly as the page shows it:

          Defined in header <future>
          enum class launch : /* unspecified */ {

              async =    /* unspecified */,
              deferred = /* unspecified */,        (since C++11)
              /* implementation-defined */

          };

std::launch is a BitmaskType. It specifies the launch policy for a task executed by the std::async function.

The following constants denoting individual bits are defined by the standard library:

• std::launch::async — the task is executed on a different thread, potentially by creating and launching it first.
• std::launch::deferred — the task is executed on the calling thread the first time its result is requested (lazy evaluation).

In addition, implementations are allowed to:

• define additional bits and bitmasks to specify restrictions on task interactions applicable to a subset of launch policies, and
• enable those additional bitmasks for the first (default) overload of std::async.

💅 Defect reports 💅

The following behavior-changing defect reports were applied retroactively to previously published C++ standards:

• DR LWG 2102 — applied to C++11; behavior as published: std::launch was an implementation-defined type; correct behavior: it is not implementation-defined.

🫶 See also 🫶

• async (C++11) — runs a function asynchronously (potentially in a new thread) and returns a std::future that will hold the result (function template).

xoxo bestie 💖 source: http://cppreference.com • version/date: 2024.06.10 • page: std::launch(3) ✨🫶