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tretetex
Asked:2020-12-27 22:39:07 +0000 UTC2020-12-27 22:39:07 +0000 UTC

AutoResetEvent.WaitOne() 什么时候不带参数返回 false？

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有几个重载AutoResetEvent.WaitOne()
当信号触发时signal.Set()，所有重载中的方法WaitOne()都会返回true。
在超时重载中，当超时到期时signal.WaitOne(timeout)返回。false

那么没有参数的重载signal.WaitOne()呢？
她可以只回来true，永远不回来false吗？

c#

1 个回答

  1. Best Answer

    WaitOne()调用另一个重载：

    https://referencesource.microsoft.com/#mscorlib/system/threading/waithandle.cs,212

    public virtual bool WaitOne ()
{
    //Infinite Timeout
    return  WaitOne(-1,false);
}

    接下来是静态方法调用InternalWaitOne：

    https://referencesource.microsoft.com/#mscorlib/system/threading/waithandle.cs,235

    [System.Security.SecurityCritical]  // auto-generated
internal static bool InternalWaitOne(SafeHandle waitableSafeHandle, long millisecondsTimeout, bool hasThreadAffinity, bool exitContext)
{
    if (waitableSafeHandle == null)
    {
        throw new ObjectDisposedException(null, Environment.GetResourceString("ObjectDisposed_Generic"));
    }
    Contract.EndContractBlock();
    int ret = WaitOneNative(waitableSafeHandle, (uint)millisecondsTimeout, hasThreadAffinity, exitContext);

    if(AppDomainPauseManager.IsPaused)
        AppDomainPauseManager.ResumeEvent.WaitOneWithoutFAS();

    if (ret == WAIT_ABANDONED)
    {
        ThrowAbandonedMutexException();
    }
    return (ret != WaitTimeout);
}

    WaitOneNative然后调用 WinAPI 函数WaitForSingleObjectEx。所以WaitOne没有参数true，要么返回要么抛出AbandonedMutexException。因为如果指定了无限超时，它将WaitForSingleObjectEx无法返回状态。WAIT_TIMEOUT

    https://docs.microsoft.com/en-us/windows/desktop/api/synchapi/nf-synchapi-waitforsingleobjectex

    • 3

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