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LockRecursionException Class

.NET Framework (current version)
 

The exception that is thrown when recursive entry into a lock is not compatible with the recursion policy for the lock.

Namespace:   System.Threading
Assembly:  mscorlib (in mscorlib.dll)

System.Object
  System.Exception
    System.Threading.LockRecursionException

[SerializableAttribute]
[HostProtectionAttribute(SecurityAction.LinkDemand, MayLeakOnAbort = true)]
public class LockRecursionException : Exception

NameDescription
System_CAPS_pubmethodLockRecursionException()

Initializes a new instance of the LockRecursionException class with a system-supplied message that describes the error.

System_CAPS_protmethodLockRecursionException(SerializationInfo, StreamingContext)

Initializes a new instance of the LockRecursionException class with serialized data.

System_CAPS_pubmethodLockRecursionException(String)

Initializes a new instance of the LockRecursionException class with a specified message that describes the error.

System_CAPS_pubmethodLockRecursionException(String, Exception)

Initializes a new instance of the LockRecursionException class with a specified error message and a reference to the inner exception that is the cause of this exception.

NameDescription
System_CAPS_pubpropertyData

Gets a collection of key/value pairs that provide additional user-defined information about the exception.(Inherited from Exception.)

System_CAPS_pubpropertyHelpLink

Gets or sets a link to the help file associated with this exception.(Inherited from Exception.)

System_CAPS_pubpropertyHResult

Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.(Inherited from Exception.)

System_CAPS_pubpropertyInnerException

Gets the Exception instance that caused the current exception.(Inherited from Exception.)

System_CAPS_pubpropertyMessage

Gets a message that describes the current exception.(Inherited from Exception.)

System_CAPS_pubpropertySource

Gets or sets the name of the application or the object that causes the error.(Inherited from Exception.)

System_CAPS_pubpropertyStackTrace

Gets a string representation of the immediate frames on the call stack.(Inherited from Exception.)

System_CAPS_pubpropertyTargetSite

Gets the method that throws the current exception.(Inherited from Exception.)

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetBaseException()

When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.(Inherited from Exception.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetObjectData(SerializationInfo, StreamingContext)

When overridden in a derived class, sets the SerializationInfo with information about the exception.(Inherited from Exception.)

System_CAPS_pubmethodGetType()

Gets the runtime type of the current instance.(Inherited from Exception.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_pubmethodToString()

Creates and returns a string representation of the current exception.(Inherited from Exception.)

NameDescription
System_CAPS_proteventSerializeObjectState

Occurs when an exception is serialized to create an exception state object that contains serialized data about the exception.(Inherited from Exception.)

LockRecursionException is thrown for several reasons, including the following:

  • If a thread tries to enter an instance of ReaderWriterLockSlim recursively, but the instance does not support recursion.

  • If a thread tries to enter a ReaderWriterLockSlim instance in write mode or upgradeable mode when the thread initially entered the lock in read mode. This represents a potential deadlock and therefore is not allowed.

  • If allowing one more level of recursion would exceed the maximum value for the internal storage counter used to track recursions. This limit is so large that applications should never encounter it.

The following example shows two causes of LockRecursionException when using the ReaderWriterLockSlim class. The program creates a ReaderWriterLockSlim by using the default constructor, which disallows recursion. The program then starts a thread that enters the lock in read mode. The thread tries to enter the lock recursively in read mode, and catches the resulting exception. Finally, the thread tries to enter write mode, which would create a potential for deadlocks. The thread catches the resulting exception.

using System;
using System.Threading;

class Example
{
    // By default, the lock recursion policy for a new 
    // ReaderWriterLockSlim does not allow recursion.
    static ReaderWriterLockSlim rwls = new ReaderWriterLockSlim();

    static void ThreadProc()
    {
        Console.WriteLine("Acquire the reader lock.");
        rwls.EnterReadLock();

        try
        {
            Console.WriteLine("\nAttempt to acquire the reader lock recursively:");
            rwls.EnterReadLock();
        }
        catch (LockRecursionException lre)
        {
            Console.WriteLine("{0}: {1}", 
                lre.GetType().Name, lre.Message);
        }

        try
        {
            Console.WriteLine("\nAttempt to acquire the writer lock recursively:");
            rwls.EnterWriteLock();
        }
        catch (LockRecursionException lre)
        {
            Console.WriteLine("{0}: {1}", 
                lre.GetType().Name, lre.Message);
        }
    }

    static void Main()
    {
        Thread t = new Thread(ThreadProc);
        t.Start();
        t.Join();
    }
}

/* This code example produces output similar to the following:

Acquire the reader lock.

Attempt to acquire the reader lock recursively:
LockRecursionException: Recursive read lock acquisitions not allowed in this mode.

Attempt to acquire the writer lock recursively:
LockRecursionException: Write lock may not be acquired with read lock held. This pattern is prone to deadlocks. Consider using the upgrade lock.
 */

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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