Question

I have a class that has a decimal property accessible from multiple threads

public class MyObject
{
    public decimal MyProperty{get; set;}
}

Should i use locks inside of get & set?
I understand that decimal is not the type operations with are atomic and decimal uses 96 bits.

Buy it feels very awkward to write locks only for these kinds of types – especially if you are not entirely sure why you doing this.

Answer 1

No, operations on decimal are not atomic.

The CLR only guarantees atomicity for reading/writing 32 bit values, and reference sized values. A decimal consists of multiple 32 bit ints, and operations on it are thus not atomic.

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But usually properties don’t need to be thread safe. Typically you use locking on a higher level, where the code knows more about what locking you need.

Even if you’d use locking in the property getter and setter, a simple operation like MyProperty+=1 wouldn’t be thread safe.