Interlocked.CompareExchange Method (Double, Double, Double)
Compares two double-precision floating point numbers for equality and, if they are equal, replaces the first value.
Assembly: mscorlib (in mscorlib.dll)
static member CompareExchange : location1:float byref * value:float * comparand:float -> float
The destination, whose value is compared with comparand and possibly replaced.
The value that replaces the destination value if the comparison results in equality.
The value that is compared to the value at location1.
Return ValueType: System.Double
The original value in location1.
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 CompareExchange is the original value in location1, whether or not the exchange takes place.
The following code example demonstrates a thread-safe method that accumulates a running total of Double values. Two threads add a series of Double values using the thread-safe method and ordinary addition, and when the threads complete the totals are compared. On a dual-processor computer, there is a significant difference in the totals.
In the thread-safe method, the initial value of the running total is saved, and then themethod is used to exchange the newly computed total with the old total. If the return value is not equal to the saved value of the running total, then another thread has updated the total in the meantime. In that case, the attempt to update the running total must be repeated.
Available since 8
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Available since 8.1