Gemstone Threading Library
Show/Hide TOC

# AsyncLockTryEnterAsync(TimeSpan) Method

Attempts to obtain exclusive access to the lock.

## Definition

Namespace: Gemstone.Threading
Assembly: Gemstone.Threading (in Gemstone.Threading.dll) Version: 1.0.156 -- Release Build+d9c3c9ff423cb81bc351c70c72797c5bc686ec2e
C#
View Source Request Example

    public Task<IDisposable> TryEnterAsync(
    	TimeSpan timeout
    )

VB
View Source Request Example

    Public Function TryEnterAsync (
    	timeout As TimeSpan
    ) As Task(Of IDisposable)

C++
View Source Request Example

    public:
    Task<IDisposable^>^ TryEnterAsync(
    	TimeSpan timeout
    )

JavaScript
View Source Request Example

    function TryEnterAsync(timeout);

#### Parameters

timeout TimeSpan
  The amount of time to wait before failing to take the lock.

#### Return Value

Task IDisposable
A task that, if cancelled, indicates the lock was not taken, and must be awaited to obtain the token that will release the lock on Dispose.

## Remarks

The following illustrates an example of using try-catch to detect a failure to take the lock.

C#

    AsyncLock asyncLock = new AsyncLock();

    try
    {
        using IDisposable token = await asyncLock.TryEnterAsync();
        // Critical region
    }
    catch (TaskCanceledException)
    {
        // Lock failed
    }

The following illustrates an example of using ContinueWithTResult(FuncTask, TResult) to detect a failure to take the lock.

C#

    AsyncLock asyncLock = new AsyncLock();

    await asyncLock.TryEnterAsync().ContinueWith(async tokenTask =>
    {
        if (tokenTask.IsCanceled)
        {
            // Lock failed
            return;
        }

        using IDisposable token = await tokenTask;
        // Critical region
    }).Unwrap();

## Exceptions

TaskCanceledException | The timeout expires before the lock could be taken.

## See Also

#### Reference

AsyncLock Class
TryEnterAsync Overload
Gemstone.Threading Namespace