Event loops form the backbone of modern high-performance networking and I/O operations, yet developers often grapple with platform-specific implementations and heavyweight libraries. Enter c-events – a purpose-built, minimalist event loop library designed to provide a unified interface for Linux's epoll, macOS's kqueue, and Windows' IOCP (via wepoll) while emphasizing efficiency and low-level control.

Core Philosophy: Less Overhead, More Control

Unlike comprehensive solutions like libuv or libevent, c-events deliberately avoids becoming an all-encompassing framework. Instead, it focuses on providing a lean abstraction layer over OS-level multiplexing systems:

events_init(1024); // Initialize system
events_t *loop = events_create(60); // Create event loop
// Register file descriptor with callback
events_add(listen_sock, EV_READ, on_connection, NULL);
// Core monitoring loop
while (events_is_running(loop)) {
    events_once(loop, 5); // Process events with timeout
}

This approach eliminates "the additional memory allocations for structures not necessary" according to the project documentation. Events are persistent until explicitly removed (events_del()), with user-triggered events being single-shot by default unless configured otherwise.

Bridging Platform Divides

c-events tackles Windows compatibility head-on by creating pseudo-file descriptors (fds_t/filefd_t) that mimic Linux behavior:

  • Implements Linux-like functions (mkfifo, inotify_add_watch) on Windows
  • Uses events_new_fd()/events_assign_fd() to abstract OS-specific event mechanisms
  • Routes system calls through macros that cache parameters and redirect to correct OS routines

Coroutine-Inspired Execution Model

The library integrates concepts from the developer's c-raii project to enable coroutine-like asynchronous execution. This design allows efficient scheduling of I/O operations without traditional callback nesting:

"The behavior/process of coroutine execution... is setup for automatically creating/moving and putting coroutines in different threads. This makes using epoll, kqueue or any multiplex interface system more effective."

Thread pools (os_worker_t) handle filesystem/CPU-intensive tasks via events_add_pool(), while a separate task pool (os_tasks_t) manages event API execution across threads – addressing libuv's documented thread-safety limitations in its event loop API.

Practical Applications & Differentiation

Real-world examples demonstrate c-events' simplicity:

  • A TCP proxy requiring only async_wait() wrappers around read()/write()
  • Google-style waitGroup synchronization
  • Cross-platform named pipes (mkfifo) enabling libevent samples to work on Windows
  • Simplified implementations of libuv's DNS resolution, file streaming (uvcat), and process spawning

Developers seeking to avoid libuv's "unneeded overhead" or requiring granular control over event processing may find c-events particularly compelling. Its MIT license and CMake build system lower adoption barriers.

As event-driven architectures continue powering everything from web servers to IoT devices, minimalist alternatives like c-events offer valuable flexibility. By focusing on efficient abstraction rather than comprehensive solutions, it carves a distinct niche in the systems programmer's toolbox.

Source: c-events Documentation