Chapter 12: Writing Unsafe Rust and FFI

In the previous chapter, we learned about the network primitives built into the Rust Standard Library and saw how to write programs that communicate over TCP and UDP. In this chapter, we will conclude the book by covering a few advanced topics related to unsafe Rust and foreign function interfaces (FFIs).

We have seen how the Rust compiler enforces rules of ownership for memory and thread safety. While this is a blessing most of the time, there may be situations when you want to implement a new low-level data structure or call out to external programs written in other languages. Or, you may want to perform other operations prohibited by the Rust compiler, such as dereferencing raw pointers, mutating static variables, or dealing with uninitialized memory. Have you wondered how the Rust Standard Library itself makes system calls to manage resources, when system calls involve dealing with raw pointers? The answer lies in understanding unsafe...