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Interlocked.CompareExchange Method (IntPtr, IntPtr, IntPtr)

Compares two platform-specific handles or pointers for equality and, if they are equal, replaces one of them.

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

public static IntPtr CompareExchange (
	ref IntPtr location1,
	IntPtr value,
	IntPtr comparand
public static IntPtr CompareExchange (
	/** @ref */ IntPtr location1, 
	IntPtr value, 
	IntPtr comparand
Not applicable.



The destination IntPtr, whose value is compared with the value of comparand and possibly replaced by value.


The IntPtr that replaces the destination value if the comparison results in equality.


The IntPtr that is compared to the value at location1.

Return Value

The original value in location1.

Exception typeCondition


The address of location1 is a null pointer.

If comparand and the value in location1 are equal, then value is stored in location1. Otherwise, no operation is performed. The compare and exchange operations are performed as an atomic operation. The return value of this method is the original value in location1, whether or not the exchange takes place.


IntPtr is a platform-specific type.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0