In the section on the IDisposable interface on page 191, there is a line...

If an ImageTransformer object is destroyed without using other API calls to free those handles, their memory is lost.

Is the memory only lost until the program ends or is it lost until a reboot? Is this what is known as a memory leak?

Yes, this is an example of a memory leak.

Unfortunately, the exact behavior depends on the kind of resource that is leaking. Some objects (I think including some graphics objects) are limited on a system-wide basis, so if the program uses them all up, other programs will also suffer. That may cause weird behavior for this program and others.

I think that these sorts of leaks usually recover after the leaking program ends, but there are cases where the system could be left in a strange state. The most common example is when a program dies but leaves a file locked.

Some leaks can also mess up the system badly enough that it's hard to kill the leaking program.

The moral is, if you're using unmanaged resources, you should test with a lot of allocations and deallocations to see if there is a leak before you release the program into the wild.

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Rod

Rod Stephens, Microsoft MVP

Essential Algorithms: A Practical Approach to Computer Algorithms

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