On 09/05/07, anil kumar <anildahiya80@xxxxxxxxx> wrote:
HI Please tell me , what are the main difference between atomic and volatile variable ?
atomic refers to something that appears to the rest of the system as a single event that is either completed entirely or not at all. When speaking about atomic data types what is meant is data types that, when read or written, are always consistent. For instance, if one part of the system is writing to the variable and another part is reading the variable, then the part that is reading will either see the value before the write happens or the value after the write has completer - it'll never read a value from the variable that is only partially updated. A volatile object (variable) is an object that the compiler will not optimize access to. The volatile keyword does not guarantee that access to a variable will be atomic, so you can't use volatile instead of proper locking with a mutex, spinlock or similar.
Thanks in advance. --Anil
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