CODEWITHSUNDEEP
c#
Cornelius
Cornelius

Reputation: 3616

Getting the address location of variable

In C# how can you get the address of a variable without using the unsafe keyword. I do not want to change the address or access it, just have its location.

Upvotes: 2

Views: 4692

Answers (3)

Brian Gideon
Brian Gideon

Reputation: 48949

You will have to pin the object before extracting its address. Otherwise, the GC is free to move it around.

object variable = new object();
GCHandle handle = GCHandle.Alloc(variable, GCHandleType.Pinned);
IntPtr address = handle.AddrOfPinnedObject();

Normally you would only do this in scenarios requiring some type of unmanaged interop. However, even then there is rarely a need for this type of manual manipulation.

Upvotes: 4

D Stanley
D Stanley

Reputation: 152566

Since .NET moved variables in managed memory around all the time, you need to "pin" the variable, then get its location with GCHandle:

static void Main()
{

    string myVar = "This is my string";

    GCHandle handle = GCHandle.Alloc(myVar, GCHandleType.Pinned);
    IntPtr pointer = GCHandle.ToIntPtr(handle);

    Console.WriteLine(pointer);

    handle.Free();

}

However, I believe this actually moves the original variable to a new location referenced by the GCHandle, and it doesn't work for all types - only blittable types.

Upvotes: 7

Daniel Hilgarth
Daniel Hilgarth

Reputation: 174329

You can't.
And for good reason, because the address is not fixed. It can - and will - be moved around by the memory management of the CLR.

Upvotes: 17

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