update to 0.9.0 release (2021-12-20)

updated files: example_tcp_server.zig signal_posix.zig

pike

A minimal cross-platform high-performance async I/O library written in Zig.

Features

• Reactor/proactor-based I/O notification support
  • epoll (linux)
  • kqueue (darwin)
  • i/o completion ports (windows)
• Async POSIX socket support
  • bind, listen, connect, accept
  • read, recv, recvFrom
  • write, send, sendTo
  • get/set socket options
• Async Windows socket support
  • bind, listen, connect, accept
  • read, recv, recvFrom
  • write, send, sendTo
  • get/set socket options
• Async signal support
  • signalfd for epoll (linux)
  • EVFILT_SIGNAL for kqueue (darwin)
  • SetConsoleCtrlHandler for i/o completion ports (windows)
• Async event support
  • sigaction (posix)
  • SetConsoleCtrlHandler (windows)

Design

Notifier

A Notifier notifies of the completion of I/O events, or of the read/write-readiness of registered file descriptors/handles.

Should a Notifier report the completion of I/O events, it is designated to wrap around a proactor-based I/O notification layer in the operating system such as I/O completion ports on Windows.

Should a Notifier report the read/write-readiness of registered file descriptors/handles, it is designated to wrap around a reactor-based I/O notification layer in the operating system such as epoll on Linux, or kqueue on Darwin-based operating systems.

The Notifier's purpose is to drive the execution of asynchronous I/O syscalls upon the notification of a reactor/proactor-based I/O event by dispatching suspended asynchronous function frames to be resumed by a thread pool/scheduler (e.g. kprotty/zap).

Handle

A Handle's implementation is specific to a Notifier implementation, though overall wraps around and represents a file descriptor/handle in a program.

Subject to the Notifier implementation a Handle's implementation falls under, state required to drive asynchronous I/O syscalls through a Handle is kept inside a Handle.

An example would be an intrusive linked list of suspended asynchronous function frames that are to be resumed upon the recipient of a notification that a file descriptor/handle is ready to be written to/read from.