How's memory allocated for a static variable?

Question

In the below program

Class Main{

static string staticVariable = "Static Variable";
string instanceVariable = "Instance Variable";

public Main(){}

}

The instanceVariable will be stored insided the memory allocated for object instance. Where will the static variable go, Is it stored in the object instance itself or some where else? If its stored some where else, how are the memory locations connected?

Answer 1

Memory for static variables are normally held in some rooted (and hidden) object[]. This can be seen doing a !gcroot on the object in WinDbg (with SOS).

Just to add, these references can never be GC'ed (unless you null the field), as I discovered recently.

Answer 2

Static variable is stored on the heap, regardless of whether it's declared within a reference type or a value type. There is only one slot in total no matter how many instances are created.

This heap is separate from the normal garbage collected heap - it's known as a "high frequency heap", and there's one per application domain.

You will find the below resource useful Static variable demystified

Answer 3

For instance in C++ staic variables are allocated in global memory space with global variables. Compiler uses special naming convention to know that this variable belongs to the class.