Question

请考虑以下代码。每次运行代码时，输出始终为0和3。我确信它与单个实例有关，但没有任何解释为什么会这样。如果您能帮助我理解这一点，那将是很棒的。谢谢您的帮助。

发生这种情况是因为每次初始化变量时，变量都指向堆中的另一个位置吗？

def assert_either_selector(selector_1, selector_2)
  if has_selector?(selector_1, wait: false)
    assert_selector(selector_1)
  elsif has_selector?(selector_2, wait: false)
    assert_selector(selector_2)
  else
    flunk("Failed to match either selector \nExpected to find either: \n\t#{selector_1} or #{selector_2}")
  end
end

Answer 1

这是线程安全的简单情况，而不是线程安全

问题是RunOp有一个内部Helper，由于线程睡眠和延迟，该内部public class RunOp { private SemaphoreSlim slim = new SemaphoreSlim(1,1); //Has to do something with single instance Helper _configHelper; public async Task Run() { await slim.WaitAsync(); _configHelper = new Helper(); var val = await _configHelper.Process(); Console.WriteLine(_configHelper.GetList.Count); slim.Release(); } // or public async Task Run() { Helper configHelper = new Helper(); var val = await configHelper.Process(); Console.WriteLine(configHelper.GetList.Count); } }被覆盖并显示不一致的结果。

这是线程安全版本

Data <- structure(list(Date = c("2018-05-25", "2018-05-25", "2018-05-25", 
"2018-05-25", "2018-05-25", "2018-05-25", "2018-05-25", "2018-05-25", 
"2018-05-25", "2018-05-25", "2018-05-25", "2018-05-25", "2018-05-25", 
"2018-05-25", "2018-05-25", "2018-05-25", "2018-05-25", "2018-05-25", 
"2018-05-25", "2018-05-25", "2018-05-25", "2018-05-25", "2018-05-25", 
"2018-05-25", "2018-05-25"), Time = c("08:36:46.203", "08:36:47.552", 
"08:36:48.222", "08:36:49.429", "08:36:50.409", "08:36:51.471", 
"08:36:52.393", "08:36:53.422", "08:36:54.482", "08:36:55.436", 
"08:36:56.454", "08:36:57.552", "08:36:58.385", "08:36:59.473", 
"08:37:00.368", "08:37:01.477", "08:37:02.399", "08:37:03.596", 
"08:37:04.457", "08:37:05.593", "08:37:06.595", "08:37:07.582", 
"08:37:08.506", "08:37:09.579", "08:37:10.586"), Date_Time = c("2018-05-25 08:36:46.203", 
"2018-05-25 08:36:47.552", "2018-05-25 08:36:48.222", "2018-05-25 08:36:49.429", 
"2018-05-25 08:36:50.409", "2018-05-25 08:36:51.471", "2018-05-25 08:36:52.393", 
"2018-05-25 08:36:53.422", "2018-05-25 08:36:54.482", "2018-05-25 08:36:55.436", 
"2018-05-25 08:36:56.454", "2018-05-25 08:36:57.552", "2018-05-25 08:36:58.385", 
"2018-05-25 08:36:59.473", "2018-05-25 08:37:00.368", "2018-05-25 08:37:01.477", 
"2018-05-25 08:37:02.399", "2018-05-25 08:37:03.596", "2018-05-25 08:37:04.457", 
"2018-05-25 08:37:05.593", "2018-05-25 08:37:06.595", "2018-05-25 08:37:07.582", 
"2018-05-25 08:37:08.506", "2018-05-25 08:37:09.579", "2018-05-25 08:37:10.586"
)), class = "data.frame", row.names = c(NA, -25L))

我知道这只是一个学术问题，但这确实应该重构并重新考虑

实例变量

1 个答案: