Thread.VolatileRead Method (Single)
Reads the value of a field. The value is the latest written by any processor in a computer, regardless of the number of processors or the state of processor cache.
[Visual Basic] Overloads Public Shared Function VolatileRead( _ ByRef address As Single _ ) As Single [C#] public static float VolatileRead( ref float address ); [C++] public: static float VolatileRead( float* address ); [JScript] public static function VolatileRead( address : float ) : float;
- The field to be read.
The latest value written to the field by any processor.
VolatileRead and VolatileWrite are for special cases of synchronization. Under normal circumstances, the C# lock statement, the Visual Basic SyncLock statement, and the Monitor class provide easier alternatives.
On a multiprocessor system, VolatileRead obtains the very latest value written to a memory location by any processor. This might require flushing processor caches.
Even on a uniprocessor system, VolatileRead and VolatileWrite ensure that a value is read or written to memory, and not cached (for example, in a processor register). Thus, you can use them to synchronize access to a field that can be updated by another thread, or by hardware.
Calling this method affects only a single memory access. To provide effective synchronization for a field, all access to the field must use VolatileRead or VolatileWrite.
Note In C#, using the volatile modifier on a field guarantees that all access to that field uses VolatileRead or VolatileWrite.
Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Common Language Infrastructure (CLI) Standard