wtf is fiber?

Boost.fiber is a C++ library that lets a program juggle multiple tasks at once within a single thread of execution. Instead of relying on the operating system to forcibly swap between tasks, which is expensive and unpredictable, this library lets each task voluntarily pause itself and hand control over to the next one. The result is a way to handle many concurrent operations with very little overhead. Under the hood, it works by taking a snapshot of exactly what the program is doing at any moment, things like CPU registers, the instruction pointer, and the stack pointer, and saving it. When a task yields, that snapshot is tucked away and another task's saved state is restored. This "context switch" is extremely fast, typically taking fewer than 100 CPU cycles compared to thousands of cycles for a traditional thread switch. It's designed to feel familiar to developers who have used standard threading libraries, offering similar classes and functions for managing and synchronizing tasks. Developers building high-performance applications, like game engines, real-time trading systems, or network servers, would use this when they need to run thousands of concurrent tasks without the heavy performance penalties of operating system threads. For example, a game might use it to run character AI, physics calculations, and audio processing side by side, where each task can politely step aside when it hits a natural stopping point. The cooperative model means the developer has precise control over when tasks switch, avoiding the unpredictable pauses that preemptive threading can introduce. The project requires a C++11 compiler or newer. The README doesn't go into detail about the specific Zig build system mentioned in the repository description, so the focus remains squarely on the core C++ library itself and its approach to lightweight, cooperative multitasking.