Professional C# and .NET, 2021st Edition

13Managed and Unmanaged Memory

WHAT'S IN THIS CHAPTER?

• Allocating space on the stack and heap at runtime
• Garbage collection
• Releasing unmanaged resources using destructors and the System.IDisposable interface
• Understanding the syntax for using pointers in C#
• Using the Span type
• Using Platform Invoke to access native APIs on Windows and Linux

CODE DOWNLOADS FOR THIS CHAPTER

The source code for this chapter is available on the book page at www.wiley.com. Click the Downloads link. The code can also be found at https://github.com/ProfessionalCSharp/ProfessionalCSharp2021 in the directory 1_CS/Memory.

The code for this chapter is divided into the following major examples:

• PointerPlayground
• PointerPlayground2
• QuickArray
• SpanSample
• PlatformInvokeSample

All the projects have nullable reference types enabled.

MEMORY

Variables are stored on the stack. The data they reference can be on the stack (structs) or on the heap (classes). Structs also can be boxed so objects on the heap are created. The garbage collector needs to free up unmanaged objects that are no longer needed from the managed heap. When you use native APIs, you can allocate memory on the native heap. The garbage collector is not responsible for memory allocated on the native heap. You have to free this memory on your own. There's a lot to consider with regard to memory.

When you use a managed environment, you can easily be misled into not paying attention to memory management because the garbage collector ...