Every Box, Vec, and String in a Rust program eventually asks the global allocator for memory. By default, that request goes to the system allocator—malloc on Unix, HeapAlloc on Windows—or to jemalloc on some targets. The #[global_allocator] attribute is the mechanism that replaces that default with a custom implementation, routing every heap allocation in the…

A bare-metal Rust program runs on hardware that has no operating system. There is no main function called by a runtime, no heap allocator, no file system, and no console. The CPU powers on, reads a vector table from a fixed address, jumps to a reset handler, and begins executing your code. Everything that std…

WebAssembly is a portable bytecode format that runs in browsers, Node.js, and standalone runtimes. Rust compiles to it efficiently because the language has no garbage collector and produces small binaries. But the raw Wasm interface is narrow: it passes integers and floats, not strings, objects, or DOM nodes. wasm-bindgen is the bridge that lifts that…

Every atomic operation in Rust carries an Ordering argument, and that argument is the entire reason atomics are difficult. The atomicity itself is simple: an operation that cannot be split by another thread. The ordering is where the reasoning lives. It determines which other memory operations the compiler and CPU are allowed to move around…

A lock-free data structure is one where at least one thread can always make progress, even when other threads are stalled, preempted, or killed mid-operation. This guarantee is stronger than a mutex-based structure, where a thread holding the lock can block every other thread indefinitely. The tool that makes lock-free programming possible in Rust is…