c# - Where is == operator defined in Class "object"?

Question

I searched the source code of FCL, and I got confused that string.Equals() uses Object.ReferenceEquals(), and Object.ReferenceEquals() uses == operator to jugde. And then I can't find how the == operator is defined.

So where is the original operator defined?

question from:https://stackoverflow.com/questions/34172634/where-is-operator-defined-in-class-object

Answer 1

This is an operator that the language uses to validate that two values are the same. When your code would be compiled this operator would be compiled appropriately in CIL and then when we will be executed by the CLR the two values would be compared to be checked if they are the same.

For instance, this is the CIL code for the Main method:

that the compiler produces for the following program (it's a console application):

class Program
{
    static void Main(string[] args)
    {
        int a = 3;
        int b = 4;
        bool areEqual = a == b;
        Console.WriteLine(areEqual);
    }
}

Note the IL_0007 line. There a ceq instruction has been emitted. This is that you are looking for, the == operator.

Important Note

This is happening when the == is not overloaded.