Linux中的异步Swift处理无法正常工作 [英] Asynchronous Swift processing in Linux not working

问题描述

我试图了解Swift 4.0异步处理在Linux中如何工作。

I'm trying to understand how Swift 4.0 asynchronous processing works in Linux.

查看文档和一些答案我想到了一个简单的例子：

After looking at the documentation and some answers on SO I came up with this simple example:

import Dispatch
import Glibc

DispatchQueue.main.asyncAfter(deadline: .now()) {
    print("Done!")
}

print("Sleeping for 2 seconds...")
usleep(2 * 1_000_000)

print("Exiting...")

但是，仅打印：

Sleeping for 2 seconds...
Exiting...

为什么它不打印完成！吗？我想念什么？我该如何写一个简单的并行处理示例？

Why does it not print Done!? What am I missing? How do I write a simple parallel processing example?

推荐答案

我认为问题出在使用 main 队列。

I think the problem was using the main queue. If I instead create a new queue, it works as expected.

import Dispatch
import Glibc

DispatchQueue(label: "worker").asyncAfter(deadline: .now()) {
    print("Doing work...")
    usleep(1 * 1_000_000)
    print("Work done")
}

print("Sleeping for 2 seconds...")
usleep(2 * 1_000_000)

print("Exiting...")

打印出预期结果：

Sleeping for 2 seconds...
Doing work...
Work done!
Exiting...

这篇关于Linux中的异步Swift处理无法正常工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！