Rory Primrose

Learn from my mistakes, you don't have time to make them yourself

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How does the GC handle circular references?

I am a little curious about how the garbage collector cleans up CLR objects. From what I understand, it will wait until objects are de-referenced and then will go through a couple of generations (as required) to release objects from memory.

The following is a simple scenario of GC:

Object A that has a reference to B that has a reference to C. When A goes out of scope, the GC can collect it. When it removes A, B is has a reference count of 0 and can also be removed and then likewise for C as B is removed.

Side question: does this happen in the same GC cycle or is this over three GC cycles?

Ok, simple enough. But how does the GC handle the following scenario:

Object A has a reference to B which has a reference to C. C has a reference back to B.

When A goes out of scope, is B available for the GC as it is still referenced by C? How does the GC handle these circular references?

Written on April 13, 2007