operator++ in VB.NET - Interlocked.Increment
Per the discussion here, one of the answers seems to imply that by using a code converter from C# to VB.NET, that the operator++ applied to an int should be replaced by System.Math.Max(开发者_如何学PythonSystem.Threading.Interlocked.Increment(current),current - 1))
, I wondered if this is actually correct?
If so, why is it correct? I didn't think that operator++ would be implemented as an Interlocked.Increment operation? I didn't even think it was threadsafe. I'm failing to see who these two are the same, and then why the answer to the question linked to, even works?
I tried it and it produces the correct result. AFAIK, .NET has no such thing as undefined behaviour, as C++ does.
Can anybody clarify?
You can do x += 1
in VB.Net. Not as elegant as x++, but better than x = x + 1.
Interlocked.Increment is for making your add operation thread-safe. You may not need it at all.
EDIT: Also, if it wasn't clear, there is no ++ operator in VB, I don't get why, but well...
C# operator++ does not use interlocked semantics. It is equivalent to x=x+1
.
No, it's not a correct replacement for current++
because current++
returns the unchanged value of current
(post-increment), while
System.Math.Max(System.Threading.Interlocked.Increment(current),current - 1))
returns the incremented value (pre-increment).
I got this same code from a C# to VB converter http://www.developerfusion.com/tools/convert/csharp-to-vb/ and that difference changed the behavior of the program.
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