C++核心準則CP.4:按照任務(wù)思考問題,而不是線程

CP.4: Think in terms of tasks, rather than threads

CP.4:按照任務(wù)思考問題，而不是線程

Reason（原因）

A?thread?is an implementation concept, a way of thinking about the machine. A task is an application notion, something you'd like to do, preferably concurrently with other tasks. Application concepts are easier to reason about.

線程是實現(xiàn)層面的概念，一種理解機器動作的方式。任務(wù)是應(yīng)用層面的觀念，你希望它可以和其他任務(wù)并發(fā)執(zhí)行。應(yīng)用概念更容易理解。

Example（示例）

void some_fun()
{
    std::string msg, msg2;
    std::thread publisher([&] { msg = "Hello"; });       // bad: less expressive
                                                         //      and more error-prone
    auto pubtask = std::async([&] { msg2 = "Hello"; });  // OK
    // ...
    publisher.join();
}

Note（注意）

With the exception of?async(), the standard-library facilities are low-level, machine-oriented, threads-and-lock level. This is a necessary foundation, but we have to try to raise the level of abstraction: for productivity, for reliability, and for performance. This is a potent argument for using higher level, more applications-oriented libraries (if possibly, built on top of standard-library facilities).

除了async()以外，標準庫功能都是低層次，面向機器，線程/鎖層次的。這些作為基礎(chǔ)有必要，但是我們必須努力提高抽象的層次：為了生產(chǎn)性，為了可靠性，也為了性能。這是一個事關(guān)使用更高層次，更加面向應(yīng)用的庫的具有重大影響的話題（如果可能，將其構(gòu)建在標注庫功能的頂層）。

Enforcement（實施建議）

???

原文鏈接

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#cp4-think-in-terms-of-tasks-rather-than-threads

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