SpinLock.Enter Method (Boolean)

.NET Framework (current version)

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Acquires the lock in a reliable manner, such that even if an exception occurs within the method call, lockTaken can be examined reliably to determine whether the lock was acquired.

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

public void Enter(
	ref bool lockTaken


Type: System.Boolean

True if the lock is acquired; otherwise, false. lockTaken must be initialized to false prior to calling this method.

Exception Condition

The lockTaken argument must be initialized to false prior to calling Enter.


Thread ownership tracking is enabled, and the current thread has already acquired this lock.

SpinLock is a non-reentrant lock, meaning that if a thread holds the lock, it is not allowed to enter the lock again. If thread ownership tracking is enabled (whether it's enabled is available through IsThreadOwnerTrackingEnabled), an exception will be thrown when a thread tries to re-enter a lock it already holds. However, if thread ownership tracking is disabled, attempting to enter a lock already held will result in deadlock.

If you call Exit without having first called Enter the internal state of the SpinLock can become corrupted.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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