12

Here is a meaningless extension method as an example:

public static class MyExtensions
{
    public static int MyExtensionMethod(this MyType e)
    {
        int x = 1;
        x = 2;

        return x
    }
}

Say a thread of execution completes upto and including the line:

x = 2; 

The processor then context switches and another thread enters the same method and completes the line:

int x = 1;

Am I correct in assuming that the variable "x" created and assigned by the first thread is on a separate stack to the variable "x" created and assigned by the second, meaning this method is re-entrant?

Ben Aston
  • 53,718
  • 65
  • 205
  • 331

3 Answers3

14

Yes, each thread gets its own separate local variable. This function will always return 2 even if called by multiple threads simultaneously.

Mark Byers
  • 811,555
  • 193
  • 1,581
  • 1,452
2

Yes, that's a correct assessment. x is a method-local variable, and won't be shared between invocations of MyExtensionMethod.

Michael Petrotta
  • 59,888
  • 27
  • 145
  • 179
0

Quite simply, yes. A static method only means that the method can be called without an object. The local variables within the method are still local.